Render in place - noise from hardware synthesizer MIDI tracks in process

Hello! I have a question about in-place rendering. I have a simple project where there are some MIDI tracks for hardware synthesizers and some MIDI tracks for VST instruments. When I render one of the VST instrument tracks to audio (whether muted or unmuted) I hear all MIDI tracks for hardware synthesizers in the background. One big noise that continues until the VST track is rendered. Why is this happening and is there any way to change it? Thanks.

Maybe I’ll modify my post a bit… What I meant was that when rendering a MIDI track of a VST instrument to audio using Render in place, I can hear the MIDI tracks of the hardware synths in the background as if they are rendering too but in reality this is not the case… I can hear them playing at a very fast rate as long as the rendering is going on…