FPS in lobby drops after a couple matches

Hello!

I wanted to play Apex, but I've got an issue. When I start playing my FPS is all good solid 60. After the first match though the FPS in the lobby drops to 45-50. After one or two more games the FPS in the lobby is down to around 20. My in match FPS is still solid 60 though. It's a very weird problem and I don't know why I've got it. Any ideas?

Thanks a lot!