I will report on the progress.
I changed it to another camera (600D) and tried it, it worked normally.
I tried again by exchanging it with 550D and it started working without problems.
I do not know the reason why it did not work properly, but now it is working properly.
I also tried it a couple of times.
Again, it may become impossible to control the focus, preview or shooting may become impossible.
It is unstable, and the state without repeatability continues.
I do not know what is the cause.
Problem is in your setup, now i have initialized photo session M33, NGC281, M31 ( mosaic ) ..with last git compiled, and is all OK!!
I have all attached in RaspberryPI3 via indiwebmanager ( I use old version of IndiWebManager ).