Ahh.. For VST i don't know what it can be, since i never use as a VST.
All i can think of that some samplerates or bitrates somewhere does not match.
Yeah. I gave up and switched to the standalone version. Everything is up, but it's too early to say if the problem is gone. But it seems to work acceptable so far. My Amiga module-tunes are themselves prone to generate pops (no interpolation), so it's a very manual labor to figure out what's normal and what's not.
Thanks for leading me in the right direction. StereoTool has an awesome sound. When I was a community DJ back in the 90s, what is does would easily had cost a fortune and a half to get in Orban-stuff. Ok, it's not dirt cheap, but for what it gives you, I will not complain.