Maybe Snoke did bridge their minds, which inadvertently solidified their bond and made them become a Dyad in the Force. So Snoke/Palpatine’s own machinations led to their undoing once again.
Pretty sure this is what Hal is going for. Although, if it was my trilogy of sequel fan edits I’d go all in on the “they’ve been a dyad for a really long time” approach. It just adds to the overall mysticism of the story (which I like about Star Wars), wherein the force hand-selected the two of them at some point to become a dyad when they didn’t even know each other.