Continuity mistake: In the scene where Lister is talking to human Kryten, just before Lister sees the photos, keep an eye on Lister's hat. It is perched on top of his head with about an inch of hair showing, yet the next shot shows the hat covering all of the hair, then it goes back to an inch of hair showing again. There is no time for Lister to have adjusted his hat between cuts. It is clear the line had to be re-shot. (00:12:35)
Continuity mistake: Kryten has three spare heads but in 'The Last Day' in series 3, he only packed away one head. (00:18:40)
Continuity mistake: When Kryten decides to be a mechanoid again, Lister gets up and grabs his jacket and swings it around his shoulders. The camera cuts to Kryten for a second then back to Lister, who now has his jacket on fully. The amount of time the camera was away from Lister would make this impossible for him to put the jacket on that quickly. (00:22:15)
Continuity mistake: When Lister has been made smaller, one shot shows him holding the bazooka, but the next shot shows him with his hand lowered. (00:25:30)
Continuity mistake: When Lister sarcastically thanks the Cat for visiting him, Lister looks forwards, but in the next shot is looking at the Cat. (00:03:35)
White Hole - S4-E4
Continuity mistake: When Kryten & Lister are talking to the toaster at the start of the episode, Lister's locks disappear then reappear over his right shoulder. (00:01:55)
White Hole - S4-E4
Continuity mistake: When Kryten tells the toaster not to offer Lister any grilled bread products, Lister is looking down at the table behind him. In the next shot he is looking over his shoulder at the camera. (00:02:50)
Suggested correction: Lister can only see M-Corp products and M-Corp employees. Cat is not an employee of JMC or M-Corp, so he disappears. Lister is the only member of the crew who is employed by M-Corp at this point.
Suggested correction: Cat was a descendant of the cat Lister brought aboard Red Dwarf. Would it be possible that the new owners might have stricter security controls, and Lister was sent to Stasis for a different reason?
Andy Benham ★
Inventing Deux ex machina explanations for a plot hole doesn't make it any less of a plot hole. M-Corp erases all of the Jupiter Mining Corporation's equipment, personnel and infrastructure from Lister's life. In no way is Cat a part of that. He has no connection at all to the Jupiter Mining Corporation, and until he meets him in Episode 1 no connection to Lister, either.
If M-Corp only erased JMC equipment from Lister's life, then Kryten, who belongs to DivaDroid and not the JMC, wouldn't have disappeared either. He disappears as he doesn't belong to M-Corp, not because he belongs to the JMC. Cat has no connection to M-Corp, as he wasn't a part of the JMC (as you pointed out), and is therefore erased for Lister.