Here is what else I am seeing (I hope this helps).
When I start wsjt-x the zbitx frequency changes to 14.074 which is the default ft8 frequency. I am able to change the zbitx band ONE time with wsjt-x to whatever e.g. 40m and the zbitx frequency changes to 7.074. But if I try to change the band again it does not work.
If I shut down wsjt-x and restart it then I have the same results. Can only make one change.