Attempting to open the developer console by pressing F9 or typing /console in the chat does nothing 100% of the time, unless you’re the place owner.
Using LogService you can find the following error:
This bug must’ve started happening recently, as it was working fine yesterday.
I don’t know whether it happens on non-PC platforms as well or not.
Edit: Seems like the issue is related to the fflag UseCanManageForDeveloperIconClient
This bug was confirmed in my end. I’ve checked on all different platforms to see I’m able to reproduce the bug, and sure enough, the developer console did not show up.
I have tested these platforms:
Windows (also includes Windows 10) (version-d8b93c3784384690)
macOS (10.15.4)
iOS 13 + iPadOS
Android 10
However, the only time it shows up was on your own places as far as I know.
I usually ask my players to send a screenshot of their Developer Console whenever they encounter errors in-game, but with this bug, they can no longer do that.
I hope Roblox fixes this soon, as this bug has had a detrimental effect on my debugging.