Recently, I have noticed in a bunch of games exploiters with innapropriate usernames such as this for example. I discovered that the cause of this was similar to the ways exploiters changed their AccountAge and MembershipType recently and developed a quick patch until roblox fixes it.
game.Players.PlayerAdded:Connect(function(v) if v.DisplayName ~= v.Name then v:Kick('DisplayName spoofing detected.') end end)
All you need to do is add this into ServerScriptService and it will detect and kick any exploiter attempting to join with a modified DisplayName.
Hope this will help until roblox themselves can push a fix to this.