I have updated the post to make it more clear what's happening.

One DateTime object, with a specific date and time, is being subtracted from another specific DateTime object.

In reply to Re^2: I can't subtract one DateTime objects from each other to get a DateTime::Duration in days by Cody Fendant
in thread I can't subtract one DateTime object from another to get a DateTime::Duration in days by Cody Fendant

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