Hi @PredictiveRules, I'm glad you were able to find a workaround. Can I ask where you are copying from? If possible, I would recommend importing instead of copy+paste. In my experience, JMP is better at guessing the correct date and time formatting on import.
Another idea is to change the format you are copying from, if possible, to something like "02 Jun 2026", making it easier for JMP to recognize the format.
This setting in the Preferences may also be relevant: 
In any case, being familiar with the display format and input format concepts described in this link is a useful skill in JMP, as these kinds of date/time formatting issues tend to come up again and again. Once I became familiar with all the concepts from that article, working with "Datetimes" in JMP became much easier.