Critical Breaking Bug with Audio Units version 3 Midi Processors in Logic Pro X 10.5.1

Logic Pro X has a critical bug when using Audio Units version 3 Midi FX.

The issue is very easy to reproduce:

What happens:

When Audio Unit v3 MIDI FX is inserted on instrument, the instrument will play and produce audio output reliably only when the instrument is currently selected track. If another track is selected, the instrument will not play even the MIDI FX Plugin is currently receiving the midi. The instrument will loose audio and will not play or the midi is not correctly passed.

MIDI FX Plugins Audio Unit v3 appears 8x duplicated in Logic Pro X plugin menu

This issue happens with any MIDI FX processor Audio Unit version 3

Replies

I think it might be a good idea to file a radar for the issues you listed. From what I can see Apple engineers don't check these forums regularly.