[BUG] Weekly usage jumped from 0% to ~60% after two short conversations; "Approaching weekly limit" banner contradicts displayed 27%/13%

### Preflight Checklist

- [x] I have searched [existing issues](https://github.com/anthropics/claude-code/issues?q=is%3Aissue%20state%3Aopen%20label%3Abug) and this hasn't been reported yet
- [x] This is a single bug report (please file separate reports for different bugs)
- [x] I am using the latest version of Claude Code

### What's Wrong?

On Max (5x). My weekly usage period reset on Tuesday, September 8, 2026. Shortly after the reset I had **two short conversations** on Fable 5.1 — brief exchanges, no long-running or agentic tasks. My Fable usage indicator then jumped from **0% to approximately 60%**.

Later the same day, after running only three or four short tasks, I received an **"Approaching weekly usage limit"** banner. At that exact moment the usage panel showed:

| Metric | Value |
|---|---|
| All models | 27% used (resets Tue 7:00 AM) |
| Fable | 13% used (resets Tue 7:00 AM) |
| Current session | 49% used |

The banner and the displayed percentages contradict each other. The banner stated the limit resets on September 15, consistent with the period having started September 8 — so hitting the limit on day one of a fresh period does not match my actual usage.

The banner has since **disappeared on its own** with no change on my side.

### What Should Happen?

Usage should accumulate proportionally to actual token consumption, and the warning banner should be consistent with the displayed usage percentages.

### Error Messages/Logs

```shell

```

### Steps to Reproduce

Not reliably reproducible on demand. Observed sequence:

1. Weekly period resets (Tue, Sep 8, 7:00 AM)
2. Two short conversations on Fable 5.1
3. Fable usage indicator jumps from 0% to ~60%
4. Three to four additional short tasks later that day
5. "Approaching weekly usage limit" banner appears while panel shows 27% / 13%
6. Banner disappears on its own

### Claude Model

None

### Is this a regression?

Yes, this worked in a previous version

### Last Working Version

_No response_

### Claude Code Version

1.46388.4

### Platform

Anthropic API

### Operating System

Windows

### Terminal/Shell

Terminal.app (macOS)

### Additional Information

### Why this looks like a metering issue, not normal usage

1. **The jump was not gradual.** Normal usage accumulates incrementally. Mine went 0% → ~60% after two short conversations.
2. **The banner contradicted the panel.** 27% / 13% is nowhere near a limit.
3. **The banner self-resolved**, suggesting a display or accounting inconsistency rather than genuine quota exhaustion.
4. This pattern resembles the widespread drain reported in #41930 (March 2026), where users saw jumps such as 21% → 100% on a single prompt, later attributed in part to two prompt-caching bugs inflating token costs 10–20×.
### Environment

- Plan: Max (5x)
- Date: September 8, 2026
- Models: Fable 5.1, plus Claude Code sessions
- Interfaces: claude.ai web, Claude Code
- Note: weekly limit was showing as "temporarily boosted (50% higher through September 13)" at the time

### What Would Help

No repository files, tests, or entry points are identified. Start by investigating the usage-metering and warning-banner paths using the reported September 8 sequence, displayed percentages, and banner state. Done means usage tracks actual consumption and the warning agrees with the usage panel without resolving incorrectly.

索引モデルが issue の本文から書いたものです。