Are you using any default value for the date search parameter? Using current date/time instead of begin of current day could cause this behavior.
Does this attribute have the "localize" option turned on or off? It should be off for DateTime attributes that don't use a time component.
If it's already turned off, check to see if you use any date math functions in microflows. For example, there are 2 functions to add days:
When you are operating on non-localized DateTimes, you should use the UTC functions. Not doing so can cause incorrect time zone adjustments to be applied.