Hi Ivan,
I am experiencing a similar issue with date/time/calendar.
@Nick_HE did some helpful research and discovered:
“(Interestingly, it doesn’t matter whether this new column’s format is “Date” or “Date and Time”. I thought setting the column to date and just making the formula =dateStart would do the trick, but the event times get preserved deep inside somewhere).”
I have no solutions yet either, but will let you know if I discover anything.