I had an opportunity to use a QHY5lll 462C planetary camera the other night. It works well for capture and live view works fine. However there is a major issues with SER recording. After the recording stops the camera is put into a state waiting for the buffer to offload and save the recording. I gave it a lengthy amount of time to finish, but it never saved the file or became responsive.

Running Raspbian Buster 65bit, Pi 4 8GB with SSD system drive. KStars 3.5.5 Beta, recently self compiled.

OK. I Realize I did not have logs available for my initial post. But I have since had a chance to make some.
Is an example of the camera becoming unresponsive after a SER recording triggered directly within the INDI Driver Control Panel. I also attempted to capture images afterwards. Incidentally the SER video was saved, however it was not finalized properly. According to SER player it was damaged and required a recovery attempt to play. Which it did successfully.

 In this example the log shows the SER recording working correctly! The only difference is I found no issues when triggering it to record from the Live Video Stream Window.

I find it highly unusual that the recording completes successfully with the stream window record button, but not from within the driver control. By my understanding they should be equivalent.