Forum Moderators: open
It's hard to know what the internal workings of AOL are. You know they like to do all sorts of customized things for/to their users, so my guess is that they haven't got all that sorted out - but that's just a guess.
When they started using Netscape/Gecko in their Compuserve division quite a while back, I was also surprised that the AOL 8 general release was based on IE.