Logic Pro X - Midi Controlled Effect troubles

Just about had it with Apple and their special edition versions of everything. I’ve finally managed to get my plugin showing up as a MIDI-controlled effect with sidechain input (a synth with audio input).

My custom synth is constantly rendering a 53 note at full velocity on playback which doesn’t make sense to me. Logging the midi messages it does not show. It only happens with this type of build and I also have pretty strict monophonic logic so it shouldn’t even be rendering 2 notes at the same time.

Funnily enough, the frequency of this note changes with the set buffer size too. Purposefully played notes do not follow this behavior.

No issues whatsoever in any other DAWs I’ve tested, including the AU version.

Now before I go digging deeper in my own silly mistakes (very possible), I just want to check with you guys if you’ve experienced anything similar and if my configuration is set up correctly.

Plugin characteristics:
Plugin MIDI input (only)

AU Main type:

Passes auvaltool test with flying colors.

Bus properties I believe are set up correctly and allow me to route things as intended, probably unrelated to the midibuffer issues but yeah.

Macbook Pro M1 2020, Ventura 13.6.3
Logic Pro X 10.8.1
Latest develop branch

I’m hoping that I’m just overlooking some configuration. In that case, it would be nice to nail down the recipe for this and keep it for anyone’s future endeavors, it’s been pretty tricky to piece together the scattered information thus far.