+1 the Error Appeard after the Upgrade from 4.12 to 4.13 and only if I am playing in multiple PIE Windows (Number of Players > 1). No crash if I open one instance of PIE nore in the Build version.
I got a workaround by making minor changes to the derived classes so that the Engine realiesed that they have changed and want to recompile them. The result is that I can start the Project with 2 or more (in my case 3) instances of the PIE window. Everything works fine again. But when I close the Engine (using the close Buttons of the Engine itself, saving all changes) and reopen it, the error appears agian.
I tried to duplicate the dreived classes and delete the original once, but tthat did not fix it either.