FastPath can't handle TMap (maybe any other container type too) in AnimGraph causes this crash.
FastPath copies TMap property to the AnimNode member property directly like MemCopy.
So two properties point the same address.
At garbage collection, The pointer will be released twice.
As a workaround, Wrapping TMap with struct works fine.
Because it's handled as ECopyType::StructProperty.
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-86550 in the post.