I know, seemed like no one could figure out why or where that exactly came from.
I was baffled when it was brought up so I googled it and there's quite a bit of discussion. There was some of the usual where people refuse to admit it was wrong "because they were taught that in school" (so of course it couldn't possibly be wrong
), although plenty were WTF when they found out. Only thing they could come up with is that there was a rumor that it was due to a typo, but that didn't seem to hold up all that well.
There were a lot of people all over the world that were supposedly taught the mn instead of mm, including French. I was surprised at the amount of people that were adamant that they were taught that in school and that they thought dilemma was a "bastardized modern American spelling". It wasn't just a certain time period either, people claimed to have learned it that way from the 1950s to the 2000s.
You should write a newspaper columm about it.
I should! I'm gonna be honest, I think that just went right over my head (I'm not getting what you're going for or referencing - are you even or should I be taking it on face value?).