Mostly the font LOL
Sounds silly, but IT guys said it was a problem and they couldn't do anything about it.
I never figured out the rhyme or reason to it, but some would be unreadable on my phone. To read them, I'd have to hit reply and then read the prior email it automatically populated — which created a new draft every time. So my outlook would wind up full of drafts. It was very annoying. No issues on the apple.