[BUG] Max 20x: ~5x increase in usage consumption with identical workflow after Feb 27 global reset

Preflight Checklist

• [x] I have searched existing issues 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?

Since the Feb 27 global rate limit reset (prompt caching bug hotfix), my daily usage consumption on Max 20x plan has increased ~5x — from a consistent ~5-6% per day to ~25% per day — with zero changes to my workflow, tools, or amount of work.
Additionally, my weekly reset day shifted from Thursday to Friday after the global reset.
Environment:

Plan: Max 20x ($200/month)
Model: Claude Opus 4.6
Claude Code version: [UZUPEŁNIJ - sprawdź: claude --version]
Platform: Windows 11 + macOS (M1)
Tools: Claude Code CLI, claude.ai, Claude Desktop with MCP tools

Before (~Feb 27): ~5-6% daily usage, consistent for weeks
After (~Feb 27): ~25% daily usage, same exact workflow
Related: #29680 (cycle date shift after Feb 27 reset), #9424 (weekly limits issues)

What Should Happen?

Daily usage consumption should remain consistent (~5-6% of weekly budget) when workflow and usage patterns haven't changed. Max 20x should provide 20x Pro usage as advertised.

Error Messages/Logs

Steps to Reproduce

Be a Max 20x subscriber using Claude Code + claude.ai with Opus 4.6
Track daily usage % before and after Feb 27, 2026 global reset
Maintain identical workflow (same number of conversations, same complexity, same tools)
Observe ~5x increase in daily consumption rate

Claude Model

Opus

Is this a regression?

Yes, this worked in a previous version

Last Working Version

2.1.49

Claude Code Version

N/A — I use Claude Desktop app, not Claude Code CLI

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Other

Additional Information

This suggests either token counting changed after the Feb 27 hotfix, prompt caching efficiency decreased, or usage calculation methodology was silently modified. At 25%/day I effectively get ~4 days before hitting the weekly cap, making the Max 20x plan significantly less valuable.
I'd appreciate transparency on whether usage calculation or prompt caching behavior has changed post-hotfix.
Note: This issue affects Claude Desktop app (with MCP tools) and claude.ai, not Claude Code CLI which I don't use in this case. Filing here because usage limits are shared across all surfaces.