No bug, and no manual mistake.
Ive tested the concept in a stand-alone-project and the traces work fine.

That is, using IGNORE_PUSH allows the trace to ignore other entities
with matching 'group' numbers, as long as larger than zero...
So no need to use "c_ignore" when you only want to ignore one group.

AND there is no problem combining it with USE_BOX, it still work OK.
As does USE_BOX on its own. It works fine there.

I HAVE YET TO TEST WITH LEVEL-GEOMETRY.... but I think it is
unlikely to yeild any problems, cause in my 'problem' code it
was failing on entities as well as geometry....

[EDIT] No problems with geometry either.
Obviously my "funky" code is doing something "TOO funky"...