True, but I believe the rng to spawn the gobs happens at rift creation. So you could be abandoning a rift before you meet the gob pack. I've been in many pub games where someone had hit a gob pack after the rift had been closed and timer is counting down. Also, I will always complete a rift that has a gob pack at the front, as I'll often run into another set before the end. Anecdotal I know, but it has been true for me.
Same for me here
When farming DBs I typically run the whole Rift. Makes more sense to me though.
UE Multi for sure.