Claude Code v2.1.23

Released Jan 29, 2026 (7 months ago).

"References this build" means the issue body mentions running 2.1.23 (from the bug-report template). It reflects report volume, not a proven defect count — an issue may mention a version without being caused by it. First-party data from the anthropics/claude-code tracker.

Top issues reported on v2.1.23

Ranked by community engagement (reactions and comments).

• [BUG] Getting "invalid beta flag" error despite CLAUDE_CODE_DISABLE_EXPERIMENTAL_BETAS=1
  Resolved 💬 16 👍 12 #21676
• [BUG] prompt-caching-scope-2026-01-05 beta header sent even when enablePromptCaching and useAnthropicBetaHeaders are set to false
  Open 💬 1 👍 15 #21644
• [BUG] claude code freezes 2.1.27
  Resolved 💬 5 👍 10 #22182
• [BUG] Conversation chain breaks mid-session - earlier messages lost on resume
  Resolved 💬 8 👍 9 #21617
• [BUG] Claude Code v2.1.27 freezes with 100% CPU on Synology NAS (Linux 4.4 kernel) — v2.1.25 works fine
  Resolved 💬 8 👍 8 #22097
• [BUG] /compact always fails with "Conversation too long" since v2.1.23 (regression)
  Resolved 💬 5 👍 9 #21853
• [BUG] Claude Code stating session limits hit and rejecting requests despite token quota being available
  Resolved 💬 3 👍 8 #21661
• [BUG] NO_PROXY stopped working in 2.1.23
  Resolved 💬 13 👍 4 #22752
• Hook scripts fail on Windows: backslash paths misinterpreted by Git Bash
  Resolved 💬 3 👍 7 #21878
• [BUG] Atlassian MCP Server Connection Timeout (SSE)
  Resolved 💬 2 👍 7 #21685
• API Error: 500 {"type":"error","error":{"type":"api_error",...
  Resolved 💬 3 👍 6 #22772
• [BUG] Skill frontmatter `model:` field documented but not working
  Resolved 💬 3 👍 6 #21679
• [BUG] Session resume fails with "Invalid signature in thinking block" - thinking block signatures not persisted
  Resolved 💬 5 👍 5 #21726
• [BUG] /resume index suddenly missing 80% of sessions
  Resolved 💬 3 👍 5 #21610
• [BUG] ECONNRESET on corporate network - TLS fingerprinting blocks Bun while curl/Node.js work
  Resolved 💬 5 👍 4 #21652
• [Feature Request] Custom slash commands missing `ide_opened_file` context tag
  Open 💬 1 👍 5 #21658
• [BUG] "Jupyter notebook detected" Connect button injects mcp__jupyter tool reference, but tool is not available
  Resolved 💬 2 👍 4 #21912
• [BUG] update to 2.1.25 don't work on windows
  Resolved 💬 11 👍 1 #21815
• [BUG] Thai Combining Characters Not Rendered in Claude Code TUI
  Resolved 💬 4 👍 3 #21711
• [Bug] IDE detection fails when running Claude Code in JetBrains Rider terminal
  Resolved 💬 3 👍 3 #22011
• [Feature Request] Add font size configuration for Claude Code VS Code extension UI
  Resolved 💬 3 👍 3 #21769
• Korean IME composition text appears below cursor position instead of at cursor
  Resolved 💬 3 👍 3 #21660
• Claude Code creates tmp/attachments folder in project directory on every session start
  Open 💬 3 👍 3 #21602
• [BUG] Built-in slash commands hidden from autocomplete when too many skills are installed
  Resolved 💬 5 👍 2 #22020
• [BUG] Visual Studio Code extension - $PATH variable is not loaded to bash tool invocations
  Resolved 💬 8 👍 1 #21728
• [Bug] Performance degradation: Claude Code unacceptably slow on max model
  Resolved 💬 4 👍 2 #21686
• [BUG] Skills/commands with disable-model-invocation: true appear in autocomplete but fail when invoked
  Resolved 💬 3 👍 2 #24042
• [Feature Request] Allow programmatic session naming via CLI flag or model tool
  Resolved 💬 3 👍 2 #21810
• [BUG] Assistant text messages not written to transcript - only thinking blocks persist
  Resolved 💬 8 #21751
• [BUG] Repeated session crashes/aborts when processing meeting notes with subagent
  Resolved 💬 5 👍 1 #21730

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