Host lagging / high ping when in a party

[rogermorse]

Just tried some matches with a new 'mate'. He had terrible ping and lag, he checked other games everything was fine. He played rocket league again and said ok it's fixed. We were in the party, he was lagging again with 180+ ping.

We redid the party, this time I was the party leader, result: I had the same problem and he was fine. I had 180+ ping with lags, he had his normal 44.

what the hell ?