Oab not updating exchange 2016 ccr
One affected public-folder based OAB distribution and the other affected web-based distribution.
This can be especially challenging when there are separate teams managing AD & Exchange; meaning sometimes things can slip through the cracks.
After the updates, it now sits in the 20-30% range.
So regardless, we saw much better performance & stability after updating the Domain Controllers.
The event logs on the DC gave the below output: The logs were saying that the process was crashing, leading to the Domain Controller restarting (see image below).
The easiest path of troubleshooting lead towards moving the FSMO roles to another server & seeing if the issue followed it.