Time related stuff sure is messy.
Someone ended up asking on one of the FreeBSD mailing lists, and it seems that they test for it:
* https://lists.freebsd.org/pipermail/freebsd-stable/2020-Nove...
So at least when it comes to the FreeBSD kernel and ntpd, there's nothing to worry about there. Userland code may be a different matter of course.
Time related stuff sure is messy.