In fact these columns contain text looking like dates not real dates. You can see this because data is left aligned which indicates text ( when there is no forced alignment of course).
One of the ways to change text to real dates is to select the column ( one colmun at a time) select the Data tab - Select Text to columns and click Finish.
Now you should see everything right-aligned, and thus real dates

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Using O365 v2503 - Did you know you can thank someone who helped you? Click on the tiny scale in the right upper hand corner of your helper's post