Downloadable Assets Disappear for Tiers 2 and 3

Summary: Downloadable assets (WordPress plugin zip files) are intermittently removed from product tiers 2 and 3, while tier 1 remains unaffected. This results in customers being unable to download their purchased plugins.

Steps to Reproduce: Set up a FluentCart product with 3 pricing tiers. Add a WordPress plugin zip file as a downloadable asset to each tier (using local storage). Complete test purchases and verify downloads work initially. Wait for an unspecified period of time.

Expected Behavior: All three tiers should retain their assigned downloadable assets permanently, allowing customers to download the plugin regardless of which tier they purchased.

Actual Behavior: Tier 1 downloads remain accessible consistently. Tiers 2 and 3 downloadable assets disappear intermittently. When checking the tier settings, only tier 1 shows the download file.

Impact: Customers who purchased tiers 2 or 3 cannot download their purchased plugin. Manual re-addition of assets is required multiple times. This causes customer complaints and poor user experience.

Environment: Storage is local storage only. Product type is WordPress plugins with multiple pricing tiers configured.

Additional Context: This issue has occurred multiple times, requiring repeated manual re-addition of the download files to tiers 2 and 3.

Question: What could be causing the downloadable assets to be removed only from the higher tiers while tier 1 remains unaffected?​​​​​​​​​​​​​​​​