In some cases *indefinitely *prior to 4.17: “Assets that are only referenced by pins inside active Blueprints will now correctly be garbage collected. This means that if you use LoadAsset to load something and do not store it for future usage, it will no longer stay in memory forever until the loading Blueprint is destroyed.”
The GC was improved over the years and sped up but it was still an issue for widgets in 4.21. As of now, not sure, I’ve been manually keeping track of widgets and trashing them when numbers do not add up.
It will not be cleaned up. From my experience the result will be valid for as long as the calling object is valid *and *the return value actually points at something valid.
The problem arises when the opposite situation takes place, you attempt to destroy an object but the GC goes “ah, no, no - something is still referencing it” (the return value) so it’s going to be *pending kill *forever. I believe that *most *of those kinks have been ironed out, though.