Well, 2.11.0 is overdue for an update: see the posting guide.
You've confused the printed representation with the object. If there
is an issue, it is in the formatting (and hence printing) of
fractional dates before the epoch ("1970-01-01 00:00"). As the help
page says
It is intended
Dear all,
I would like point out a potential bug (or at least inconsistency) in the
way the R base package converts numeric numbers to dates. Specifically,
consider the following two calls:
> as.Date(0.5, origin="1969-12-31")
[1] "1970-01-01"
> as.Date(0.5, origin="1970-01-01")
[1] "1970-01-01"
