[Bug] Claude fails to complete simple mechanical tasks with repetitive instructions

Bug Description
ABYSMAL PERFORMANCE

I asked Claude to edit a markdown file with tables, and pad the tables with spaces - a very simple and mechanical task.
It did not comply with instructions and kept over-thinking and not executing the task.
This looks like a major degradation of performance to me. Almost 60k tokens / $3 wasted on this - task not completed.

Environment Info

• Platform: darwin
• Terminal: iTerm.app
• Version: 2.1.138
• Feedback ID: de8fd9f9-3947-470d-a88a-0af0a0283731

Errors

[{"error":"Error: Request was aborted.\n    at makeRequest (/$bunfs/root/src/entrypoints/cli.js:51:6192)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-05-10T01:09:10.918Z"}]