[sttrqiss]

I'm getting similar functionality. Try entering the time as 00:02:50 rather than just 02:50. That's the only way i seem to be able to fix this.

this is correct, when you format the cell to mm:ss it will only display what you have input into that cell

so for 2mins 50secs it will display 02:50 instead of 0hours 2mins 50secs which is 00:02:50

however

you still must input into the cell as 00:02:50, simply putting 02:50 into the cell Excel will think that is 2hrs and 50mins by default. whether or not you can change this behaviour I don't know.