Excel date format is wrong after setting whole worksheet to capitals

Hi,

One of our users asked me to have all text in a sheet in capitals so I fixed this by adding this code to the sheet :

Private Sub Worksheet_Change(ByVal Target As Range)
    Dim cell   As Range
    On Error Resume Next
    Application.EnableEvents = False
    For Each cell In Target
        cell = UCase(cell)
    Next
    Application.EnableEvents = True
End Sub

This works fine, whenever she enter text, it's automatically converted to caps.

However, since I added the code, the date format has changed from Dutch (dd/mm/yyyy) to English (mm/dd/yyyy).
When she enters a date of which the first two characters are smaller than 13, it gets converted to mm/dd, and when she enters a date greater than 12, it gets correctly formatted as dd/mm.

The cell format is set to a standard date type, with the correct locale but the code somehow overwrites the format.
When I remove the code, the format is correct again.

For now I've fixed this by simply applying a custom format but I would like to know if this is normal behavior and if there's
another way to solve this?

Regards,

Dennis