Has been happening since at least since aug 19 but likely earlier than that. I reproduced with Carla standalone from latest main:
I connected B.SEQuencer MIDI output to 2 instances of Surge XT: one VST3 and one LV2.
Surge XT in the top left is a VST3 and you can see that it's output meter is not moving. The LV2 version shows output. This can be reproduced with any VST3 instrument.
Has been happening since at least since aug 19 but likely earlier than that. I reproduced with Carla standalone from latest main:
I connected B.SEQuencer MIDI output to 2 instances of Surge XT: one VST3 and one LV2. Surge XT in the top left is a VST3 and you can see that it's output meter is not moving. The LV2 version shows output. This can be reproduced with any VST3 instrument.