Welcome to the Board!
It is important to understand how Excel stores dates. It actually stores them as numbers, specifically the number of days since 1/0/1900.
So dates are really just numbers with special date formats.
The value 11522 translates to date 7/18/31, which is why you are seeing that.
If you want it to convert it over to a date according to your specifications, you can use this VBA code, which will run automatically upon manual cell entry.
Right-click on the sheet tab name at the bottom of the screen, select "View Code" and paste this VBA code in the resulting VB Editor window:
VBA Code:
Private Sub Worksheet_Change(ByVal Target As Range)
Dim d As String
If Target.CountLarge > 1 Then Exit Sub
' Fix entry if in column 1
If Target.Column = 1 Then
Application.EnableEvents = False
d = Format(Target, "000000")
Target = DateSerial(Right(d, 2), Left(d, 2), Mid(d, 3, 2))
Application.EnableEvents = True
End If
End Sub
I wrote this code to fix any entry made into column A as it happens, but we can change the range to whatever range you want to apply it to.