The 1st set of messages also seemed to show up as soon as one of my vassals (Lord Regas) finally left my trade city. Hes been setting there ever since I recruited him, so maybe his AI is broken? (this seems to have been the case)
Apparently this is an issue caused by my vassals being objective-less and trying to act on their own after owning your own kingdom, guess it's pretty common...
I've tried Alt+F4 to close the game before an auto save saved past the point the first error code appeared, this didn't work and the error code appeared at the same time again anyways.
I've tried to 'save & exit', closed the game, and brought it up again to see if maybe it just needed to reinitialize or something; this didn't work either.
I've waited 8 days for the Sultan to return Marnid to me, this didn't fix the problem either.