A licensee has reported that using FStringAssetReference::ResolveObject to reference an asset in Blueprints will result in that asset never being garbage collected. Doing the same workflow in C++ does not result in this behavior.
Please note, this only occurs in Standalone Game and packaged games.
This also occurred in 4.12.5
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-38634 in the post.