Not sure if this is an automated response or not, but Unreal Engine Issues and Bug Tracker (UE-65983) has already been reported. I am supplying additional information as the bug in question was closed as Cannot Reproduce, despite the fact that this error still exists in Version: 4.21.1-0+++UE4+Release-4.21. I have included a zip of a very minimal project that demonstrates the issue, and would likely be a significant help to locating and fixing this issue.