I have had a lot of issues, errors, site cashes after simple menu changes. Reached out to support was told that could not replicate the same errors. The sub site use looks to be a no go for now. I had to uninstal it.

I switched on WP Debug and got the following Fatal Error:

[13-Sep-2024 21:20:50 UTC] WordPress database error Table 'ligadb.wp_20_users' doesn't exist for query select * from wp_20_users where ID = 22 limit 1 made by require('wp-blog-header.php'), require_once('wp-includes/template-loader.php'), do_action('template_redirect'), WP_Hook->do_action, WP_Hook->apply_filters, FluentCommunityAppHooksHandlersPortalHandler->FluentCommunityAppHooksHandlers{closure}, FluentCommunityAppHooksHandlersPortalHandler->renderFullApp, FluentCommunityAppHooksHandlersPortalHandler->appVars, FluentCommunityFrameworkDatabaseOrmBuilder->first, FluentCommunityFrameworkDatabaseOrmBuilder->get, FluentCommunityFrameworkDatabaseOrmBuilder->getModels, FluentCommunityFrameworkDatabaseQueryBuilder->get, FluentCommunityFrameworkDatabaseQueryBuilder->onceWithColumns, FluentCommunityFrameworkDatabaseQueryBuilder->FluentCommunityFrameworkDatabaseQuery{closure}, FluentCommunityFrameworkDatabaseQueryBuilder->runSelect, FluentCommunityFrameworkDatabaseQueryWPDBConnection->select, FluentCommunityFrameworkDatabaseQueryWPDBConnection->run, FluentCommunityFrameworkDatabaseQueryWPDBConnection->FluentCommunityFrameworkDatabaseQuery{closure}
[13-Sep-2024 21:20:50 UTC] PHP Fatal error: Uncaught Exception: Table 'ligadb.wp_20_users' doesn't exist in /home/x74DWAvCyWLXRqcn/MyMultiSites/publichtml/wp-content/plugins/fluent-community/vendor/wpfluent/framework/src/WPFluent/Database/Query/WPDBConnection.php:261
Stack trace:
#0 /home/x74DWAvCyWLXRqcn/MyMultiSites/publichtml/wp-content/plugins/fluent-community/vendor/wpfluent/framework/src/WPFluent/Database/Query/WPDBConnection.php(573): FluentCommunityFrameworkDatabaseQueryWPDBConnection->FluentCommunityFrameworkDatabaseQuery{closure}()
#1 /home/x74DWAvCyWLXRqcn/MyMultiSites/publichtml/wp-content/plugins/fluent-community/vendor/wpfluent/framework/src/WPFluent/Database/Query/WPDBConnection.php(266): FluentCommunityFrameworkDatabaseQueryWPDBConnection->run()
#2 /home/x74DWAvCyWLXRqcn/MyMultiSites/publichtml/wp-content/plugins/fluent-community/vendor/wpfluent/framework/src/WPFluent/Database/Query/Builder.php(3129): FluentCommunityFrameworkDatabaseQueryWPDBConnection->select()
#3 /home/x74DWAvCyWLXRqcn/MyMultiSites/publichtml/wp-content/plugins/fluent-community/vendor/wpfluent/framework/src/WPFluent/Database/Query/Builder.php(3113): FluentCommunityFrameworkDatabaseQueryBuilder->runSelect()
#4 /home/x74DWAvCyWLXRqcn/MyMultiSites/publichtml/wp-content/plugins/fluent-community/vendor/wpfluent/framework/src/WPFluent/Database/Query/Builder.php(3705): FluentCommunityFrameworkDatabaseQueryBuilder->FluentCommunityFrameworkDatabaseQuery{closure}()
#5 /home/x74DWAvCyWLXRqcn/MyMultiSites/publichtml/wp-content/plugins/fluent-community/vendor/wpfluent/framework/src/WPFluent/Database/Query/Builder.php(3114): FluentCommunityFrameworkDatabaseQueryBuilder->onceWithColumns()
#6 /home/x74DWAvCyWLXRqcn/MyMultiSites/publichtml/wp-content/plugins/fluent-community/vendor/wpfluent/framework/src/WPFluent/Database/Orm/Builder.php(761): FluentCommunityFrameworkDatabaseQueryBuilder->get()
#7 /home/x74DWAvCyWLXRqcn/MyMultiSites/publichtml/wp-content/plugins/fluent-community/vendor/wpfluent/framework/src/WPFluent/Database/Orm/Builder.php(743): FluentCommunityFrameworkDatabaseOrmBuilder->getModels()
#8 /home/x74DWAvCyWLXRqcn/MyMultiSites/publichtml/wp-content/plugins/fluent-community/vendor/wpfluent/framework/src/WPFluent/Database/Concerns/BuildsQueries.php(346): FluentCommunityFrameworkDatabaseOrmBuilder->get()
#9 /home/x74DWAvCyWLXRqcn/MyMultiSites/publichtml/wp-content/plugins/fluent-community/app/Hooks/Handlers/PortalHandler.php(168): FluentCommunityFrameworkDatabaseOrmBuilder->first()
#10 /home/x74DWAvCyWLXRqcn/MyMultiSites/publichtml/wp-content/plugins/fluent-community/app/Hooks/Handlers/PortalHandler.php(357): FluentCommunityAppHooksHandlersPortalHandler->appVars()
#11 /home/x74DWAvCyWLXRqcn/MyMultiSites/publichtml/wp-content/plugins/fluent-community/app/Hooks/Handlers/PortalHandler.php(42): FluentCommunityAppHooksHandlersPortalHandler->renderFullApp()
#12 /home/x74DWAvCyWLXRqcn/MyMultiSites/publichtml/wp-includes/class-wp-hook.php(324): FluentCommunityAppHooksHandlersPortalHandler->FluentCommunityAppHooksHandlers{closure}()
#13 /home/x74DWAvCyWLXRqcn/MyMultiSites/public_html/wp-includes/class-wp-hook.php(348): WP_Hook->applyfilters()
#14 /home/x74DWAvCyWLXRqcn/MyMultiSites/public_html/wp-includes/plugin.php(517): WP_Hook->doaction()
#15 /home/x74DWAvCyWLXRqcn/MyMultiSites/public_html/wp-includes/template-loader.php(13): doaction()
#16 /home/x74DWAvCyWLXRqcn/MyMultiSites/public_html/wp-blog-header.php(19): requireonce('...')
#17 /home/x74DWAvCyWLXRqcn/MyMultiSites/publichtml/index.php(17): require('...')
#18 {main}

Next FluentCommunityFrameworkDatabaseQueryException: Table 'ligadb.wp_20_users' doesn't exist (SQL: select * from wp_20_users where ID = 22 limit 1) in /home/x74DWAvCyWLXRqcn/MyMultiSites/publichtml/wp-content/plugins/fluent-community/vendor/wpfluent/framework/src/WPFluent/Database/Query/WPDBConnection.php:260
Stack trace:
#0 /home/x74DWAvCyWLXRqcn/MyMultiSites/publichtml/wp-content/plugins/fluent-community/vendor/wpfluent/framework/src/WPFluent/Database/Query/WPDBConnection.php(573): FluentCommunityFrameworkDatabaseQueryWPDBConnection->FluentCommunityFrameworkDatabaseQuery{closure}()
#1 /home/x74DWAvCyWLXRqcn/MyMultiSites/publichtml/wp-content/plugins/fluent-community/vendor/wpfluent/framework/src/WPFluent/Database/Query/WPDBConnection.php(266): FluentCommunityFrameworkDatabaseQueryWPDBConnection->run()
#2 /home/x74DWAvCyWLXRqcn/MyMultiSites/publichtml/wp-content/plugins/fluent-community/vendor/wpfluent/framework/src/WPFluent/Database/Query/Builder.php(3129): FluentCommunityFrameworkDatabaseQueryWPDBConnection->select()
#3 /home/x74DWAvCyWLXRqcn/MyMultiSites/publichtml/wp-content/plugins/fluent-community/vendor/wpfluent/framework/src/WPFluent/Database/Query/Builder.php(3113): FluentCommunityFrameworkDatabaseQueryBuilder->runSelect()
#4 /home/x74DWAvCyWLXRqcn/MyMultiSites/publichtml/wp-content/plugins/fluent-community/vendor/wpfluent/framework/src/WPFluent/Database/Query/Builder.php(3705): FluentCommunityFrameworkDatabaseQueryBuilder->FluentCommunityFrameworkDatabaseQuery{closure}()
#5 /home/x74DWAvCyWLXRqcn/MyMultiSites/publichtml/wp-content/plugins/fluent-community/vendor/wpfluent/framework/src/WPFluent/Database/Query/Builder.php(3114): FluentCommunityFrameworkDatabaseQueryBuilder->onceWithColumns()
#6 /home/x74DWAvCyWLXRqcn/MyMultiSites/publichtml/wp-content/plugins/fluent-community/vendor/wpfluent/framework/src/WPFluent/Database/Orm/Builder.php(761): FluentCommunityFrameworkDatabaseQueryBuilder->get()
#7 /home/x74DWAvCyWLXRqcn/MyMultiSites/publichtml/wp-content/plugins/fluent-community/vendor/wpfluent/framework/src/WPFluent/Database/Orm/Builder.php(743): FluentCommunityFrameworkDatabaseOrmBuilder->getModels()
#8 /home/x74DWAvCyWLXRqcn/MyMultiSites/publichtml/wp-content/plugins/fluent-community/vendor/wpfluent/framework/src/WPFluent/Database/Concerns/BuildsQueries.php(346): FluentCommunityFrameworkDatabaseOrmBuilder->get()
#9 /home/x74DWAvCyWLXRqcn/MyMultiSites/publichtml/wp-content/plugins/fluent-community/app/Hooks/Handlers/PortalHandler.php(168): FluentCommunityFrameworkDatabaseOrmBuilder->first()
#10 /home/x74DWAvCyWLXRqcn/MyMultiSites/publichtml/wp-content/plugins/fluent-community/app/Hooks/Handlers/PortalHandler.php(357): FluentCommunityAppHooksHandlersPortalHandler->appVars()
#11 /home/x74DWAvCyWLXRqcn/MyMultiSites/publichtml/wp-content/plugins/fluent-community/app/Hooks/Handlers/PortalHandler.php(42): FluentCommunityAppHooksHandlersPortalHandler->renderFullApp()
#12 /home/x74DWAvCyWLXRqcn/MyMultiSites/publichtml/wp-includes/class-wp-hook.php(324): FluentCommunityAppHooksHandlersPortalHandler->FluentCommunityAppHooksHandlers{closure}()
#13 /home/x74DWAvCyWLXRqcn/MyMultiSites/public_html/wp-includes/class-wp-hook.php(348): WP_Hook->applyfilters()
#14 /home/x74DWAvCyWLXRqcn/MyMultiSites/public_html/wp-includes/plugin.php(517): WP_Hook->doaction()
#15 /home/x74DWAvCyWLXRqcn/MyMultiSites/public_html/wp-includes/template-loader.php(13): doaction()
#16 /home/x74DWAvCyWLXRqcn/MyMultiSites/public_html/wp-blog-header.php(19): requireonce('...')
#17 /home/x74DWAvCyWLXRqcn/MyMultiSites/publichtml/index.php(17): require('...')
#18 {main}
thrown in /home/x74DWAvCyWLXRqcn/MyMultiSites/public_html/wp-content/plugins/fluent-community/vendor/wpfluent/framework/src/WPFluent/Database/Query/WPDBConnection.php on line 260

It's looking for the user table for the subsite, which does not exist since multisite uses the main site's user table.