A storage vendor told me today "just because we say our API is S3-compatible doesn't mean it behaves like S3 does" which left me wondering what else the phrase "S3-compatible" might mean.
@davecturner Same interface, different behavior. What's not to understand?
Of course since there's no independent S3 interface specification, deciding what is the interface and what is not is left to each party.
It sounds like you and the storage vendor simply disagree what is (in) the interface.
A bolt with a 2cm hex head is compatible with a 2cm spanner, whether the thread is clockwise or anticlockwise.