The current “edit” GUI of input_datetime entities saves the value each time one of the following parts of a datetime is changed (individually):
- date
- hour
- minute
This is problematic if you have automations triggered by value change of such entities since the user may temporarily set a wrong date and time, even multiple times, which may trigger automations prematurely.
A better UX, in my opinion, would be a confirmation CTA (in principle like the Save button in automations editor) that the user has to activate when they are done editing.