Hello!
I was able to reproduce this behavior in the test project, see the attachment.
Select the row with the empty date in the grid, press Edit button and then press OK button in the dialog.
I guess it happens when you place two datepickers in line, and the distance between them is less than DatePicker's dropdown section.
So, those datepickers are considered to be 'overlapped', that actually is not true. That's why the error message label is shifted.
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