@juriaan hello, sorry for the late reply :)
so far, as long as I don't mess with the ports each display is connected to the pcturning on every display before the pc,starting the computer,opening the izzy file
helped with keeping the stage setup with right displays assigned for each stage. Turning on the computer first and then projectors messes up with the display order and hence the stage settings, however once I restart everything and follow the above 3 steps in the right order, things do go back to the way I want them to be.
@woland, yes, sure I will open a support ticket, thanks! but the ctrl+z trick works too.
lastly, about the hap codec: right now we are working with mp4 files since Isadora seems to be working just fine. Hopefully things will continue running smoothly as the number of the videos increase, if not, I will look deeper into this, many thnx for the tips!