Uhbik-Q Problem

[Phase47]

I have a vocal that I'm filtering (LPF). I sending this to a vocal bus, which has Uhbik-Q on it. I am finding that when the filter sweeps low, if the level of the filtered vocal falls below some threshold, Uhbik-Q (it sounds like) is muting the sound, and when it hits a certain threshold on the way up the sweep, it's pops back on with an audible click.

I bypass the Uhbik-Q and the problem goes away. Turn it back on and it mutes/clicks. Is this a bug/glitch or is there some kind of threshold thing I'm just not seeing on the controls? (Still not that familiar w/ Uhbik.)

I have to be missing something... what is it?