I have a XT-4 I had similar issue as mentioned here with the XT-3.
I spend few hours on that...
My config.:
PC with Ubuntu I5 8gen 8 GBRAM, SSD....
- KSTARS
-Indilib
-XT-4
- QHY5II (Using PHD2 as Indi camera)
So what I found is (at least in my config.), If I leave the "Force Bulb" it looks exactly the same as described in this post for the XT-3, if I turn off the "Force Bulb"
It works pretty good !