I found something odd after rolling out edge to our org.
it appears that some users do not get the IE-mode group policy applied despite being at the computer level. as a test for users that seem to be missing this piece I had them sign-in on a machine that I have tested all my IE-mode settings on. obviously when I sign-in IE-mode is active, but when I had them sign-in.. IE-mode is not active for either of them.
So that narrows it down to an issue on the user account level it would seem.
looking at the group policy again, there is a user group "authenticated users" could it be they are not in this group? It shouldn't matter since its a machine policy but I have no other explanation on how two users seem to be missing this policy.
turns out if the xml is formatted incorrectly in a recent edit new users trying to pull the xml config will encounter the error. however users that have loaded a correct xml in the past appear to be unaffected but actually are.