[Marc Esselmann]

Yes, this popping noise happens often where video clips overlap; I would say at a frequency of about 4 x out of 10. Usually the sound transition is set to crossfade. It does not matter whether the video clips are unedited (uncut) or whether they area extracts of original ones.
It happens with short clips, long clips, short movie projects or long one … When the clips are put next to each other onto the time line, the sound is clean. Overlapping the clips with, say, 1-3 seconds, with crossfade transition makes the pops come up again … Even with skf files being deleted.