There shouldn't be a permission issue since the 85-qhyccd.rules file would correctly set the USB permission for all QHY cameras.
I don't think either the problem are USB permissions. What I think is the QHY closed source library is trying to do something for which it needs superuser privileges. No idea what could it be. Accessing shared memory, system calls... Who knows. You not having the problem could be because of different kernel, or even different distros or releases. The fact remains that I can't open the Polemaster when running indi_qhy or qhy_ccd_test as a normal user, and that happened after an update that upgraded the libqhy version. On the other side, they happily run as root, or with the SETUID bit enabled in the case of qhy_ccd_test. No problem opening the stream or capturing frames as root. I do not have access to the hardware today, I'll try to grab it tomorrow, run some tests and dig into the logs...
What should I do ?
You could try running kstars as root and see if that does the trick. You probably know how to do it, but just in case you don't, open a terminal and execute the following: