[BUG] Hitting enter early on a new instruction causes it to be ignored

[Keno]

Environment

• Platform (select one):
  • [x] Anthropic API
  • [ ] AWS Bedrock
  • [ ] Google Vertex AI
  • [ ] Other:
• Claude CLI version: 1.0.21 (Claude Code)
• Operating System: macOS 15.3.2
• Terminal: iTerm2

Bug Description

When I hit enter on the text prompt while Claude is still working, the instruction appears to have been sent to claude, but it actually ignores it.

Steps to Reproduce

1. Tell Claude to do something
2. Tell it do something else while it's still working (without interrupting it)

Expected Behavior

In earlier versions of claude code, this would queue up the instruction and send it after claude is done. I'm also fine if it gets interpreted immediately.

Actual Behavior

Gets ignored completely