This episode, I believe, originally aired 1/2/68, so everything that happens from this point on is 1796. They should have done this when the episodes originally aired, but apparently they didnt realize the mistake of everything happening in 1795 until after the flashback ended.
How was that a mistake? Why do dates in 1795 or 6 have to line up with broadcast dates in real life 1967 or 8? In 1967, I think Sara sent Vicki back to a pivotal moment in the past, not just a day that happened to have the same date, only in 1795.
They never mentioned 1796 until they revisited that era later. Then for some reason, they fooled around with dates. Bradford's 1795 year of death was crudely scratched off his tombstone and made into 1796. Why bother? Then a year or two later they refer to the events as having happened in 1797. Weird.
I know that eventually there was some nonsense about dates in 1897 and 1969 lining up, but that came late in 1897, and by the way, it may have been the first use by Stokes of the phrase "parallel time", though this wasn't PT. They never established that for 1795 though. I think Victoria arrived fairly early in 1795, an early Spring maybe, and left a few months later, maybe in the Fall.