Screen time & Roblox

Hi

I am trying to limit screen time on my son’s iPad for Roblox. I have managed to limit screen time for all other apps, however for some reason Roblox is not being limited. I have tried to turn screen time on and off (under settings), have reset the device, have tried adding Roblox’s own time limit, all in varying combinations, all to no avail.

The IOS is up to date and it is an 8th gen device. I can see that others have had the same issue. Has this been resolved successfully by someone? Is there some setting in the app that I am missing?