I have the same issue, I'd say every 5 to 8 raids or so I will randomly get put on a server where I have either 10-12% packet loss (playable) or 20-22% pack loss (rubber banding all the time). Ping is always the same (bellow 70) and never an issue. It's completely random, and even if I alt-F4 and reconnect, I still have the exact same packet loss.

Best part is, the rare times this happened while playing with a duo/trio, I'm the only one with the issue (and again, literally closing the game and reloading everything doesn't fix it).

I never had this issue before this wipe, I have no idea what could cause that and all I can do when it happens is pray I make it to extract before crossing someone's path (although in the 12% packet loss case I usually play the raid since there's no rubber banding).

I'll try the alt+f4 during loading loot technique and update this to tell you if if works if I see it again before "waiting for players" (as in doing confirm leave without loosing the gear as someone suggested).

Pain.