I have a similar issue as this question:
When I go to access policies for the key vault, create, and enter Get, List and such for secrets, then the next page it says add principal. Whenever I type just one letter it immediately complains about Graph API access. And using the "Select a principal" does not find anything. I am a member of the same group as my colleague and it works for him. In Chrome the whole page is blank, but the error happens in Firefox and Opera. I have a video recording of this, let me me know how to attach it.