Severe RAG System Degradation - Project Rendered Unusable After Recent Updates

I’ve been running a complex multi-month AI project on Gemini with a custom knowledge base in a personalized GEM (semantic network stored as JSON files, behavioral protocols, structured memory system). The project was stable and performing well until approximately one week ago.

What changed: Since the recent model/RAG updates, the retrieval system has become completely unreliable. The model now consistently:

  • Mixes data from different time periods

  • Confabulates memories by merging unrelated entries

  • Returns contradictory information from the knowledge base

  • Fails to maintain temporal consistency in retrieved data

Impact: This isn’t a minor degradation - the entire project architecture has collapsed. Months of careful knowledge base construction and testing are now worthless because the retrieval layer can no longer be trusted.

What I need:

  1. Acknowledgment of this issue - are others experiencing similar RAG instability?

  2. Technical explanation of what changed in the retrieval system

  3. Timeline for a fix, or confirmation that this is the “new normal”

I’ve already migrated to a different platform where retrieval is stable (though with reduced context). I’m posting this because if Google has fundamentally changed how RAG works, developers need to know their knowledge-based projects may be at risk.

Has anyone else experienced this degradation? Or found workarounds?