Azure bug

At the company I work for, we have a RedGate installation, monitoring some Azure SQL databases.
When adding one, we encountered a weird thing. We already had 2 databases from that server in RedGate, all worked beautifully. Added a new one and booom.. RED .. Some permission issue.

Msg 300, Level 14, State 1, Line 27
VIEW SERVER PERFORMANCE STATE permission was denied on object 'server', database 'master'.
Msg 297, Level 16, State 1, Line 27
The user does not have permission to perform this action.

That was strange. We looked at all the configurations, maybe we did something wrong, maybe we forgot to add something. But no, nothing..
Compared the database and only difference was the service tier/DTU count. "Naah, that can't possible be it.."

Just before I left work, I thought "Well, it's worth a shot". So I scaled the database from 10 DTU to 50 DTU.
And low & behold, it started working... Strange.
Tried to scale it back to 20. BANG! stopped working again.. Maybe it's a bug, maybe it's a feature.
If it is a feature, it would sure have been nice to have a more descriptive error message though :)