Jacob, after testing again, the GLib error is persistent and not consistently reproducible. It was not an issue in the last version of QGC but had shown up in the version i was using before that. So something seems to have changed between versions.
It does happen before the crash sometimes and then other times happens after the crash. No real consistency, as i have stated.
As for the colors in the carpet, this is only happening after the update, not before it and i believe, is still connected with the pixellation. I do not believe it is compression artifacts.
I am using the pi camera which , i believe is causing the very green video in shallow water due to the white balance in the pi not stabilising properly with light from the surface. It seems to reduce in green intensity as i dive deeper.
These are my observations only. Test and make up your own mind.
I have to take up the offer of helping to test for reasons i don’t wish to mention on the forum.
I will be PM Rusty soon about the reason and i’m sure he will fill you in.