cspgsl,
It appears the problem with the second date relates to the "Regional Settings" having been set at "English (United Kingdom)" when this file was created or at some point in its history.
I was able to "duplicate" your results by using the following steps - which you should use to become familiar with how to change the settings, and thereby correct your problem.
a) From Windows, use Start - Settings - Control Panel.
b) In the "Control Panel" window, choose "Regional Settings".
c) If your current setting is "English (United States)", change it to "English (United Kingdom)".
d) Choose "Apply", and then "OK".
e) In a cell in your sheet, format the cell as: Category: "Date", Type: "14-Mar".
f) Now enter "Feb 23" into the cell. The result will be "1-Feb" in the cell, and on the formula bar, it will show "01/02/2023".
So, to correct your problem, I believe all you need to do, is to change (or re-set) the Regional Settings to "English (United States)" once you have the file open that is giving you the problem.
The cell containing the wrong date (showing "1-Feb" and actual date of "01/02/2023" will NOT automatically change when you change the Regional Settings. You will have to re-enter the correct date. But, after changing the Regional Settings to English (United States), entering "Feb 23" will produce the proper result - i.e. in the formula bar, it will now read "2/23/2003", and the cell will show "23-Feb".
I hope the above helps. Please advise as to how you make out.
Regards, ...Dale Watson dwatson@bsi.gov.mb.ca