XLA:TPU Compiler Bug Affecting Token Selection

8/10 High

A precision mismatch bug in the XLA:TPU compiler caused incorrect token selection by the approximate top-k operation, affecting Haiku 3.5 and potentially Sonnet 4 and Opus 3. The issue was masked by a previous workaround that was inadvertently removed.

Claude Haiku 3.5Claude Sonnet 4Claude Opus 3XLATPU
Category
performance
Workaround
none
Stage
deploy
Freshness
declining
Scope
single_lib
Upstream
wontfix
Recurring
No
Buyer Type
team
Maintainer
active

Sources

Collection History

Query: “What are the most common pain points with Claude Code for developers in 2025?”4/4/2026

In September 2025, Anthropic acknowledged bugs degrading output quality in models like Sonnet 4 and Haiku 3.5. A November 12, 2025, post: 'I thought claude was draining abnormally fast, but it seems everyone else is having the same problem.'

Query: “What are the most common pain points with Anthropic API for developers in 2025?”3/30/2026

This change inadvertently triggered a latent bug in the XLA:TPU compiler... This caused a mismatch: operations that should have agreed on the highest probability token were running at different precision levels.

Created: 3/30/2026Updated: 4/4/2026