Yes it's about that i just remember that the fix is that the worldeditor should use an other BJ for such nested functions.
I suppose a file edit is enough, you know the ones which are used by the GUI, some users have "extended" the GUI with these ones.
I mean i've already followed the generated code once, i just don't remember exactly.
Now ofc the most friendly way is just to use DestroyGroup all the times rather than expect that every GUI users will use such edited files or even more unlikely figure when use the custom script "set bj_..." or not.
Plus, maybe such edit files are not enough, a worldedit update may be needed, can't remember exactly what stuff is needed to be fixed.