Repro: Create a variable that's a TMap of String/Structs.
Make sure the struct has an array in it.
Add an element to the array.
All expanded details of the struct/array will collapse and has to be reopened every time a new element is added to the array.
All entries are collapsed.
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-92953 in the post.