Considering the other reports we've had of de jure empire weirdness, my supposition (without knowing precisely whether those issues were reported using the 2.4.3 Beta) is that some de jure bugs were fixed by Paradox in the beta that added an extra layer of problems to CK2Plus's setup of having no de jure empires at game start. Which is fine, as it's possible this has been a source of crashes since...well, since I started on the mod, so discovering the source now will save us headaches in the long run.
The only issue will be people using old saves with the new version. Can't stop them, as it's technically compatible, but it does mean a lot of weird bugs in the future. That said, it does seem as if the de jure weirdness is gone in its entirety if you simply start a new game.