[Bug] Session window consumed faster than expected with concurrent Claude Code instances

**Bug Description**
The Daily Session windows are filled extremely fast today. My amount of work that I do is the same as the last few weeks but know I reach the available Session Usage window already after a quarter of normal time. I use Opus 4.8 1M with xhigh regulary without that effect. I run 2 - 4 claude cli instances simultanously but controlled by me (not autonomous).

**Environment Info**
- Platform: win32
- Terminal: windows-terminal
- Version: 2.1.240
- Feedback ID: e42cd93b-9b3d-4497-b8a4-84bbb37d8cdf

**Errors**
```json
[]
```

Start by reproducing the report with Claude Code 2.1.240 on win32 in Windows Terminal, using 2–4 concurrent instances and the reported Opus 4.8 1M and xhigh settings. Compare session-window consumption with a single instance and collect the resulting usage data; done means identifying a reproducible cause or confirming the behavior cannot be reproduced.

Rédigé par le modèle d'indexation à partir du texte de l'issue.