A lot of methods are designed to work with pure datetime objects as args. If
the value comes from the database it will be rounded at the level of seconds
(0 microsecond). If it comes from a call do datetime.now() / datetime.utcnow()
the datetime object has a value != 0 for its mircroseconds attribute. Therefore
some methods have unpredictable results depending of the origin of the values
manipulated since the microsecond argument is missing into all the calls to
datetime.replace
Closes#15768
Laurent Mignon (ACSONE)
1dea8a53fb