Sidechain strange behavior in Pro Tools (Windows)

[jackspost]

I have discovered a strange behavior when using side chain routing. I don't know how to describe but first it seems to work normally but only on the right channel. When I change VST or send level of the side chain bus. I get some noise on every track in pro tools! Sometimes The metering of the master track is suddenly at 0 DB full scale, even when the send bus is down, independently if a VST is loaded or not.

Seems like a big bug on Pro Tools 12.5 under Windows. Only tried on mono bus, yet