Two times now, in the past two weeks or so, I've experienced a weird, major issue on Tideway Security PvE where the game runs fine throughout the whole round then suddenly goes to hell on the final checkpoint (you know, the little building past the bridge with two doorways to defend).
The minute that checkpoint opens for attack, the red server icon pops up, everyone's ping gets really high, you start rubberbanding around the map, and it seems like you're about to get dropped from the game, but you don't.
Then, once you capture the checkpoint and get into the counterattack phase, 0 enemies spawn and your team just waits around for the game to end while experiencing the most insane lag ever.
I don't think this is just a connection issue, because this exact scenario has happened to me at least two times recently.