[Bug] Claude Code modifies unrelated code when making single-line changes

Resolved 💬 5 comments Opened Dec 15, 2025 by fwends Closed Feb 14, 2026

Bug Description
asked to change one line of code changed everything And breaks everything. Why can't it just follow simple instructions rather than overdoing it, over-engineering it? All I asked it to do is add 1 line of text. That's all. And now it's turned that into a three-line. 3hour job

It's highly frustrating that sometimes it can work perfectly and another time it can't even make 1 simple change without totally screwing it up and editing loads of other files that are not related to it. When it's got a clear plan That it simply doesn't follow
And to add to that, every time it makes a change and breaks something, it says it's fixed it, comes back and says it's working. Not a single test done, nothing works, it's totally broken. The most irritating thing. thing is yes it's working that's why we had to make another script to make sure that it goes and checks its work you need to fix this nonsense

Environment Info

  • Platform: darwin
  • Terminal: tmux
  • Version: 2.0.67
  • Feedback ID:

Errors

[{"error":"Error: NON-FATAL: Lock acquisition failed for /Users/greg/.local/share/claude/versions/2.0.69 (expected in multi-process scenarios)\n    at b8R (/$bunfs/root/claude:2242:2155)\n    at XgB (/$bunfs/root/claude:2240:8651)\n    at async Vs1 (/$bunfs/root/claude:2240:11366)\n    at async dx (/$bunfs/root/claude:2242:236)\n    at async <anonymous> (/$bunfs/root/claude:2242:14255)\n    at processTicksAndRejections (native:7:39)","timestamp":"2025-12-14T08:28:04.689Z"},{"error":"Error: NON-FATAL: Lock acquisition failed for /Users/greg/.local/share/claude/versions/2.0.69 (expected in multi-process scenarios)\n    at b8R (/$bunfs/root/claude:2242:2155)\n    at XgB (/$bunfs/root/claude:2240:8651)\n    at async Vs1 (/$bunfs/root/claude:2240:11366)\n    at async dx (/$bunfs/root/claude:2242:236)\n    at async <anonymous> (/$bunfs/root/claude:2242:14255)\n    at processTicksAndRejections (native:7:39)","timestamp":"2025-12-14T08:58:05.150Z"},{"error":"Error: NON-FATAL: Lock acquisition failed for /Users/greg/.local/share/claude/versions/2.0.69 (expected in multi-process scenarios)\n    at b8R (/$bunfs/root/claude:2242:2155)\n    at XgB (/$bunfs/root/claude:2240:8651)\n    at async Vs1 (/$bunfs/root/claude:2240:11366)\n    at async dx (/$bunfs/root/claude:2242:236)\n    at async <anonymous> (/$bunfs/root/claude:2242:14255)\n    at processTicksAndRejections (native:7:39)","timestamp":"2025-12-14T09:28:05.252Z"},{"error":"Error: NON-FATAL: Lock acquisition failed for /Users/greg/.local/share/claude/versions/2.0.69 (expected in multi-process scenarios)\n    at b8R (/$bunfs/root/claude:2242:2155)\n    at XgB (/$bunfs/root/claude:2240:8651)\n    at async Vs1 (/$bunfs/root/claude:2240:11366)\n    at async dx (/$bunfs/root/claude:2242:236)\n    at async <anonymous> (/$bunfs/root/claude:2242:14255)\n    at processTicksAndRejections (native:7:39)","timestamp":"2025-12-14T09:58:05.129Z"},{"error":"Error: NON-FATAL: Lock acquisition failed for /Users/greg/.local/share/claude/versions/2.0.69 (expected in multi-process scenarios)\n    at b8R (/$bunfs/root/claude:2242:2155)\n    at XgB (/$bunfs/root/claude:2240:8651)\n    at async Vs1 (/$bunfs/root/claude:2240:11366)\n    at async dx (/$bunfs/root/claude:2242:236)\n    at async <anonymous> (/$bunfs/root/claude:2242:14255)\n    at processTicksAndRejections (native:7:39)","timestamp":"2025-12-14T10:28:05.161Z"},{"error":"Error: NON-FATAL: Lock acquisition failed for /Users/greg/.local/share/claude/versions/2.0.69 (expected in multi-process scenarios)\n    at b8R (/$bunfs/root/claude:2242:2155)\n    at XgB (/$bunfs/root/claude:2240:8651)\n    at async Vs1 (/$bunfs/root/claude:2240:11366)\n    at async dx (/$bunfs/root/claude:2242:236)\n    at async <anonymous> (/$bunfs/root/claude:2242:14255)\n    at processTicksAndRejections (native:7:39)","timestamp":"2025-12-14T10:58:05.139Z"},{"error":"Error: NON-FATAL: Lock acquisition failed for /Users/greg/.local/share/claude/versions/2.0.69 (expected in multi-process scenarios)\n    at b8R (/$bunfs/root/claude:2242:2155)\n    at XgB (/$bunfs/root/claude:2240:8651)\n    at async Vs1 (/$bunfs/root/claude:2240:11366)\n    at async dx (/$bunfs/root/claude:2242:236)\n    at async <anonymous> (/$bunfs/root/claude:2242:14255)\n    at processTicksAndRejections (native:7:39)","timestamp":"2025-12-14T11:28:04.783Z"},{"error":"Error: NON-FATAL: Lock acquisition failed for /Users/greg/.local/share/claude/versions/2.0.69 (expected in multi-process scenarios)\n    at b8R (/$bunfs/root/claude:2242:2155)\n    at XgB (/$bunfs/root/claude:2240:8651)\n    at async Vs1 (/$bunfs/root/claude:2240:11366)\n    at async dx (/$bunfs/root/claude:2242:236)\n    at async <anonymous> (/$bunfs/root/claude:2242:14255)\n    at processTicksAndRejections (native:7:39)","timestamp":"2025-12-14T11:58:05.061Z"},{"error":"Error: NON-FATAL: Lock acquisition failed for /Users/greg/.local/share/claude/versions/2.0.69 (expected in multi-process scenarios)\n    at b8R (/$bunfs/root/claude:2242:2155)\n    at XgB (/$bunfs/root/claude:2240:8651)\n    at async Vs1 (/$bunfs/root/claude:2240:11366)\n    at async dx (/$bunfs/root/claude:2242:236)\n    at async <anonymous> (/$bunfs/root/claude:2242:14255)\n    at processTicksAndRejections (native:7:39)","timestamp":"2025-12-14T12:28:04.997Z"},{"error":"Error: NON-FATAL: Lock acquisition failed for /

Note: Error logs were truncated.

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