Multiple lags and Freezing (only lasts like 3 seconds)

Hi All, 1st Post, so im sorry if its crap.
Whenever im playing, but only with 1 particular player, every 10-15 seconds, the games stops, and waits for his connection. the "Dropout screen" is displayed for 1-2 seconds then disappears. This happened over 50 times in a 35 minute game.

is there any reason for this?
or is the other players internet crap?
Has this happened to other players, if so, what was the fix?

Whenever i play with other players, this does not happen.
Thank you for any Help.
Cheers VanTurbo

could be network (use ethernet not wifi)
could be internet (is CGNAT turned off at isp? it should be)
could be slow cpu
most likely one of those, maybe some other unusual thing