Magic Video Wall out of sync

I’m trying to use the Magic Video Wall package, but the video is out of sync on some screens and not always (or so it seems to me!).
I’ve already enabled the P2P support.
Could it be a file format issue?

FullHD might be too much for the magic video wall as it needs to transform the video into their configuration placement. This is a somewhat expensive operation and FullHD might be over the limit. Do you really need the magic video wall? If your screens are planar and in a usual 2x2 or similar configuration, you might use the Video Wall player instead. It uses a cheaper method of placing the video and will work with FullHD.

Unfortunately this is not the case. For future use: with the Video Wall player is it possible to edit the position and size of the video portions that are played?

It would be nice to have a setup where you can specify what portion goes where with a test pattern that moves/resizes live as we edit on, then have it slices the video for all the screens so that even a 4K or bigger file can be used!