I checked back a few pages for certain posts, and, well, hopefully this clears up the confusion:
Yukari: "A portal to her dimension was left open. You go first?"
There is a portal in the Shadaloo base that Isis left open, a portal that leads directly to Isis' dimension. That's not the only one:
-between handling a Touhou and Beerus, all on her own, Isis was starting to get a bit overwhelmed... but still confident, as she warped away-
Yukari: -Used gap to get to where she is-
-Yukari could have always left a gap for Beerus to follow Isis, just saying- :V
There's a second portal (or "gap", in this case) that Yukari made
inside Isis' dimension itself, which she used to follow Isis when she tried to warp elsewhere. The gap is supposed to still remain, so that Beerus can follow her through it.
So, the former portal was made Isis, and the latter was made by Yukari. Both are still open.
EDIT:
'd. I hope the reference posts help at least, lol.