Yeah, the black holes can, have, and will decide at random that you will not progress, because one or two of your party members are trapped with nowhere safe to lead their tethers. It's not even the worst case, by far, of rng being the deciding factor for progression in this game, but there you have it. There's no safe pattern, no set of patterns which which to adjust, just random placement of black holes wherever the game feels like dropping them.