Screen time and Roblox

I’ve set up screen time limits on our iPad for my son. The limits all work except for the Roblox app. I set a time limit for all game apps but that didn’t seem to apply to Roblox (even though it is categorized under games). I then set up a specific time limit for Roblox. Either way, the app is never blocked regardless of how long it’s been open. Is this a known issue with Roblox, and what’s the fix? Thanks.