Major Data Entry Issue
If a cell contains the number zero, and I enter another number in that cell, the zero gets appended to the new number. For example, if I enter the number 5, Excel shows 50 in that cell instead of just 5.
Although this doesn't happen all the time, I have actually had it happen to me once out of approximately every three tries.
This is serious because people using spreadsheets automatically enter numbers into cells and always assume the that new number will replace the old. The fact that it appends the zero to the new number can cause users to end up with some pretty substantial errors.
But, I have only seen this happen when the cell contains a 0 first.
I can't believe that after 30 years something like this could be missed!
Sounds like you have some number formatting set on the cell that's not "general," bit is instead "percent" or something like that.
The next time you have it happen, can you share a file with us, by editing the original idea here and adding the file as an attachment?