Building derived data for AnimSequence does not create deterministic output. Data that is stored to the DDC is expected to be deterministic. If there is a need to store metadata that may vary between builds, e.g., for debugging or profiling purposes, that may be stored in the metadata of FCacheRecord.
Cook with -DDC-Verify=AnimationSequence and check the log for errors from cache verification that look like the example below. Lyra provides a quick repro.
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-193688 in the post.