Quick answer: Unity URP renderer feature disabled but its keyword state persisting? Keywords set by features aren't auto-cleared - explicit DisableKeyword on disable.
Outline renderer feature disabled; OUTLINE_ON keyword still active; outlines still render in some materials.
Disable keyword on feature disable
Renderer feature's OnDisable: clear its keywords.
Or use local keywords
Per-material; not affected by feature toggle.
Audit feature lifecycle
Each feature's keyword state. Symmetric set/clear.
“Renderer feature keyword state is persistent. Disable should clear.”
If you build custom renderer features, the cleanup is part of the contract. Document.