If you were to enter text in a cell in excel, and it automatically changes you can either hunt for settings for the autocomplete feature. I found though that if you insert an apostrophe the text you input will stay the same. For example
Normally 12dec07, when entered becomes 12-Dec-07
Just add an apostrophe like this ‘12dec07, and the apostrophe disappears in the cell, and the text doesn’t change automatically.