Ooh, I just thought of one. The arcade I used to work in had 2 x £5 Jackpot Simpsons machines (same board as Homers Meltdown, but in the older cabinet).
Anyway :
1) Never saw one of these give an IM (red lamps), and
2) Never saw one of them give a REPEAT on a JACKPOT.
Come to think of it, I've never seen ANY £5 Maygay machine of that type give a repeat on a jackpot, they always jump off. Bear in mind they were among the most played £5 AWPs in the arcade, and took plenty of cash, but never once saw one repeat, or give an IM.
I'm only referring to the £5 versions, it's entirely possible the higher jackpots did repeat or give an IM
I've had that machine for years and never had an IM or jackpot repeat!