There's never been any suggestion that there was an intentional 'change of continuity', so much as just the guys doing their usual riffing and prioritising - going for a solution to the episode's plot rather than worrying about such things. The Justice computer is beaten, is the point. There's no apparent aim to rewrite Dwarf lore than there is with the end of Timeslides, where Series I, II and half of III must have happened very differently since Rimmer was apparently now alive during them. They just wanted a gag to finish on - no concern was given to what this meant for the plot of Stasis Leak. (Which would have gone VERY differently had Rimmer not been a hologram looking to save his own life.) Rimmer failed to repair the drive plate. That implication is even called back in Series VIII. And, crucially, Rimmer never objects to the one key point: that his job involved repairing drive plates. Had the intention been to rewrite that continuity , that was the time to do it.