I don't think rain will make problems to the lobby, but it gives another layer of graphics that your console need to calculate and show. And since SPA is a track you can see very big part of the track at some places it could be the fault of the FPS drops I actually experienced today.
And it was something strange thing happening to the rain today, I know it came end went away today, but it stayed very long at 0% standing water. If that's a bug, it might be the reason why the lobby turned into a problem evening for us.
We also had several problems during practice in the ICGTC private lounge. People had loading bars and people disconnecting and couldn't join.
Could be that the last update from PD is messed up and that wouldn't surprise me at all, but it could be someone in here getting a free NAT2.. Meaning they shouldn't have a NAT2, but gets it because the console doesn't know how to act online.
As I explained before I have two Playstations online here and both is getting NAT2, even though only one should get it. The other one is very much behind a firewall with no ports forwarded. Still it show as NAT2.
I suspect that someone here have the same thing, the private room seems to act totally different when different people are on top (hosting the room) even with a none fixed ownership room as the ICGTC room is.