Agent seems unable to exit Plan mode

### Short summary

Agent had to be forced out of planning mode with multiple prompts

### Affected version or release

v1.1.6

### Installation context

Windows

### What happened?

I have two threads where the initial prompt was in planning mode.
Following the planning, it was almost impossible to make the agent perform work.

### Steps to reproduce

1. Start prompt in planning mode
2. Accept the plan and start implementing in Interactive or Autopilot mode
3. The agent had to be told multiple times to actually do the actions

### Expected behavior

Agent starts working once the plan is accepted and mode is changed from Plan to Interactive or Autopilot

### Additional context

Reproduce the issue on Windows with v1.1.6 by starting in Plan mode, accepting the plan, and switching to Interactive or Autopilot. Compare whether the agent begins executing work without repeated prompts; done means the mode transition reliably starts implementation.

Written by the indexing model from the issue text.