I’m surprised this bug still exists.
CCD generated duplicates or does not react to the hidden lines being OFF. Both options produce same result.
Hidden OFF - wrong output
Hidden ON - correct output
This looks to be a duplicate BUG in Clipping Drawings - doubled output - #6 by AndyPayne
@Piotr the Hidden Line toggle being on/off and not being recognized was something that I thought I fixed last week. Can you confirm which BETA version you have installed?
Ze latest
@Piotr These bugs should all be fixed in the next BETA release. Thanks for reporting it!