With all channels muted if sample or synth are passed to the filter it creates a pop/click. this is surely adding unwanted signal to the channels while they are unmuted.
I assume this means filter is running in parallel and not in line before the mixer.
this is with mod filter set to 0%
Build Date: 10 Feb 2023 9:35:00pm
JUCE Version: JUCE v6.1.6
Operating System: Windows 10
Daw: FL21.1.1 [Build 3750]
Would have added this as an edit to the original post but for some reason i’m locked out from editing op after one day. Again, poor customer experience. jfc.