The property value iterator has logic where it tries to iterate over all properties in a structure, including properties nested inside structs and containers. A licensee found a problem where if you have a TMap<Struct,int> it would skip the int properties due to the way the iteration happens.
I'll fix this and also add an automated test to validate this continues to work
Or use the steps outlined in the UDN
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-58753 in the post.