I suspect you will find this means that the camera doesn't re-focus correctly after you use set_zoom.
I have a shoot
command following the set_zoom
command after a short delay, so I didn't notice that the camera wasn't refocusing. I increased the delay, and can clearly see that the camera doesn't refocus after zooming, although it does refocus when the shoot
command is carried out.
I'll try the new test build with Servo AF off and see what happens.