Hi @nick.marchini,
This has been an ongoing battle with Microsoft. They have been imposing ever-tightening throttles at a global level, instead of at the user level. It is most noticeable during U.S. business hours.
We are working on another tactic for combating this and I am reaching out to them again.
The situation was improved until fairly recently, where it seems like their throttling logic may have been changed again.
Edit: We released more tweaks to combat the rate limiting