the issue does not apear when opening the editor, it happens when you start PIE.
And it does not only happen with custom bodys, it happens also with Manny from EPIC.
And what i did right before it happend, i upgraded from 5.2.1 to 5.4.1.
With 5.2.1 everything still works fine, so i current continue with that engine untill i find a solution.