The cache keys changed, so the old files were never read again but stayed mixed in with the new ones. With the cache in its own directory the old one can be deleted.
The aspect-ignored header blamed a processor for a decision the free axis can make too. fit-in does not letterbox, it answers smaller than the box. The s3 cache checks bucket, region and credentials, not the endpoint. A mapping onto a type the generator cannot write is refused at startup instead of quietly becoming a JPEG. And a processor name nobody knows resolves like none, which three comments and a readme line still denied.
A cache backend nobody can serve fails at startup instead of dropping
entries silently, the memory backend is bounded, a busy generator's 429
reaches the client with its Retry-After, and a 400 from the generator is
read as this service's own bug instead of a missing preview.
André Duffeck