[R] strange date problem - May 3, 1992 is NA

[Alexander Shenkin]

> is.na(strptime("5/2/1992", format="%m/%d/%Y"))
[1] FALSE
> is.na(strptime("5/3/1992", format="%m/%d/%Y"))
[1] TRUE

Any idea what's going on with this?  Running strptime against all dates
from around 1946, only 5/3/1992 was converted as "NA".  Even stranger,
it still seems to have a value associated with it (even though is.na
thinks it's NA):

> strptime("5/3/1992", format="%m/%d/%Y")
[1] "1992-05-03"

Thanks,
Allie

R