the problem with midnight is it is has no value.
as I'm sure you know, datetime is stored as a double - the bit before the decimal point is the date, expressed as the number of days since 31/12/1899 and the bit after the time expressed as the number of seconds divided by 86400, the number of seconds in a day.
so today is
?cdbl(date())
44013
and time
?cdbl(now())
44013.3842708333
midnight means no seconds so you would just get 44013 not 44013.0
the combo is a string
try this in one of the sim_time textboxes (remove formatting and input mask)
=VarType([ICRScenarioCombo].[column](2))
and it will return 8 - which is string
https://docs.microsoft.com/en-us/off...rtype-function
so the OP is trying to apply a date format to a string value - which means it attempts to convert the string to a date - and looks like loses something in the translation