I send the same bug report.
I found a workaround that works here:
start a new Kontakt 7 vst3 channel, then start a Synchron Player channel, then again a Kontakt 7 vst3 channel, then a Synchron Player channel and so on. After that, you can delete the Synchron Player channels, if you don't need them.
When you need several Kontakt vst3 instances, you can make one Kontakt 7 vst3 channel and one Synchron Player channel, select them and duplicate them as much as you want. After that select the Synchron Player channels and delete them at once.
As I said: here it works (I work on a Windows computer), perhaps it works with you?
NB: With Vienna Instruments Pro instead of Synchron Player this trick doesn't work here.