[Bug] Claude degraded performance: inconsistent error corrections across codebase

Bug Description
For approximately the past two days, I’ve felt that Claude has become “dumber,” or less intelligent. Before, whenever I pointed out an error, it would correct it everywhere necessary without me having to ask. Over the past few days, however, it only fixes the issue in one place, and I have to guide it to make the same correction elsewhere.

Fortunately, I know my code well enough to guide it, but if someone unfamiliar with the code were using it, Claude could end up introducing even more problems. Besides, we expect an AI like Claude Opus running at maximum effort to handle this automatically, without requiring constant instructions.

This has left me feeling somewhat disappointed and frustrated over the past few days because I’m taking much longer to accomplish tasks that should be quick and using more tokens than necessary.

Environment Info

• Platform: win32
• Terminal: null
• Version: 2.1.260
• Feedback ID: df325fb6-91c6-4a6f-a819-fafe0a75b5b6

Errors

[{"error":"TelemetrySafeError: VirtualMessageList: itemKeys/messages length desync (keys=1206 messages=1205 range=[1189,1206))\n    at N$t (B:/~BUN/root/chunk-9tytjqtz.js:36:26122)\n    at Sme (B:/~BUN/root/chunk-9tytjqtz.js:36:18954)\n    at Ha (B:/~BUN/root/chunk-gcsbr8vy.js:18:20017)\n    at Nu (B:/~BUN/root/chunk-gcsbr8vy.js:18:38158)\n    at Yh (B:/~BUN/root/chunk-gcsbr8vy.js:18:84182)\n    at Tg (B:/~BUN/root/chunk-gcsbr8vy.js:18:83184)\n    at Qu (B:/~BUN/root/chunk-gcsbr8vy.js:18:83013)\n    at Hh (B:/~BUN/root/chunk-gcsbr8vy.js:18:79547)\n    at Ve (B:/~BUN/root/chunk-gcsbr8vy.js:18:6254)\n    at Fe (B:/~BUN/root/chunk-gcsbr8vy.js:18:4788)","timestamp":"2026-09-18T02:08:18.047Z"}]