Trying to understand what happened to Kryton between S2E1 and S3E1

So they find Kryton in S2 E1

Then he's gone for the rest of the season

Then he returns in S3E1 with, for every version I have seen, no explanation as to where he has come from. In Wikipedia it says this for Backwards (S3E1)

"At the same time, the ship's computer Holly) underwent a transformation to become his alternate universe counterpart Hilly (Hattie Hayridge) whom he fell madly in love with, while the others came across the broken pieces of the mechanoid Kryten (Robert Llewellyn), after he crashed on an asteroid while riding Lister's space bike), leading to Lister having to salvage and rebuild him, consequentially causing him to lose his old personality."

I have never seen that in any version I have watched. Does such a version exist?