Whenever I join a new match in a PVP server the GUI Clock mod randomly disappears. However when I go back to the lobby it magically reappears again. Is there any way for me to fix this such that I can see what time it is while I'm in a match so I know how long I've been playing?

Which PvP server are you playing on?

Not something I can fix on my end without extra information. They might have limited the information players can have in the game. Thanks for giving the mod a try nonetheless!