Need an umbrella?

Go on - ask most people what Gene Kelly's most famous song and dance routine is - you know, the one where he needs an umbrella. Make sure you ask them to spell it exactly. Chances are, unless they are already aware of this Mandela Effect, they'll reply with "Singing in the rain". If they do, they will be surprised to hear it's never been called that - in fact it's "Singin' in the rain".

Many of the Mandela Effects being reported today seem trivial. Sometimes it's a minor spelling change such as this one, sometime "The" is dropped from a title etc. The reason these are of interest is the idea that slight changes are far easier, and less disruptive to timelines, than larger ones. It's almost as if a test was being performed, or a minor glitch occurred which in the grand scale of things no-one would notice.

Residue

Either it really has been changed, or an awful lot of people also got the title wrong. A Google search for "Singing in the rain" shows this clearly with plenty of hits.

Well, at the time of writing ;-)