Fruit -> Froot -> Fruit

This one appears to keep changing!

Wikipedia (currently) says the popular Kelloggs breakfast cereal was launched in 1962 as "Froot Loops". 

Several people have seen references to "Fruit Loops" and there is some evidence of this on the web. This could be explained by Kelloggs themselves changing the branding so the "OO" is styled in the form of the cereal if it was the other way round, but that's not the direction it went - the "OO" was supposed to always have been there, and the "Fruit" spelling the one it changed to, for many people.

Things gets stranger when reports come in of it changing back again!

No actual fruit

It's been suggested a name change did occur early on due to the fact the product doesn't contain any fruit. To avoid any legal issues, the change to "Froot" would have therefore made sense.There were originally 3 colors, and the mascot, Toucan Sam was brightly decorated with them. In the original commercials, his voice was provided by Mel Blanc, who was more famous for prodiving the voices of Bugs Bunny, Daffy Duck and Porky Pig.

This Mandela Effect is one of the ones with the strongest evidence for a flip flop available. That's because there are documented discussions involving people who initially came across it as a regular Mandela Effect, so were aware of it as such, but then came across the same discussion later to find it was now back to the original version when evidence is again searched on the rest of the internet. This mirrors many other such flip flops, such as Houston, we have a problem. Some are saying these flip flops are evidence of the Mandela Effect itself evolving, or, if there is indeed some intelligent controller behind it, an attempt at correcting a mistake which people have noticed.