Are you on Windows? And what is your OS system date format set to?
There is an open bug related to date format. Maybe you are experiencing this bug: Properties: Date format not following system settings
And there is a feature request to set values independent from the OS settings: Properties: let the user customize the way Dates/Times are displayed (independently from OS)
I don’t know the full details, but those are the threads I’m aware of.
(Also, that’s not what the Meta category is for, so this was moved to help. 
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