Amalgam Universe/Headscratchers

• I heard that Amalgam-related events were supposedly canon for both Marvel and DC (though for obvious reasons they could never mention them in their personal comics). And there is JLA-Avengers, which is also supposedly canon for both of them, but the two things aren't canon to each other. I understand the real reason is most likely that Kurt Busiek didn't want to deal with this stuff, but I wonder, if there exists an in-universe explanation?
  • The easy explanation would seem to be that a lot of times, the Marvel and DC characters' memories of what happened during Amalgam get fuzzy when Access isn't around... that he basically makes them recall that their universes have crossed over before, and that without him around, most of them forget about having met each other before. Either that or we can assume that JLA-Avengers actually occurred between a different DC Earth and a non-616 Marvel Earth where the Amalgam incident didn't happen.