Yes. You need to remove “MIDI Effect”. MIDI Effect is a concept that only exists in AU, and just does unexpected things in VST3.
(AAX added the concept of MIDI FX recently, but also doesn’t work with that flag and instead has it’s own flag).
Notice that even after removing that flag, MIDI output usually has to be routed manually in the DAW.
So in Studio One, you will find the MIDI output of your effect as an input into another track and NOT in the same track.
Most DAWs don’t pass MIDI between plugins in the same chain. A few like Reaper and Bitwig do, but S1/Ableton Live/Cubase/FL Studio won’t do that without manual MIDI routing.