I found a bug in Drum Leveler's Side Chain Filter

Cubase 12.0.70 and Reaper 6.81
M1 Macbook Pro Ventura 13.2.1

The SCF changes the tone of the source on low frequency drums. Lets say I set the SCF Bandpass frequency to a range of 65 - 105hz, so it listens only to the fundamental of the kick (so it ignores the snare), the kick drum comes out of the plugin sounding wildly different that it did going in. No, I did not his the S button to listen to the sidechain. It does this with all my kick mics on both kick drums. Same thing happens on Snare Top, although to a much lesser degree, if I set the SCF bandpass at 180 - 230hz to only listen to the snare fundamental, and ignore the toms.

However, there is no detectable difference when I use this same technique on the rack tom close mics. I can hear it a little bit on the floor tom close mics, but its less obvious. Let me know if you need a session from me to see whats happening. This happens equally in Cubase and Reaper.