We just released an Insider update for Outlook. This update fixes some of the issues you identified over the last couple of weeks, including:
- Fonts or images not appearing correctly in the new email editor
- Issues around editing email messages with custom fonts
- Crashes going to or from the signature editor
A couple things to note regarding build numbers:
- After you install the Outlook update, you should be on version 15.20.1 (160323).
- All other apps should still be on 15.20 (160315).