date "+%j" bug?

I was testing out:

  %j   day of year (001..366)

Since I can't run the test once per day (need it before that ;-) I was
using the --date field.

Since feb 29 is obviously the trick here, I tried:

$ date --date "02/28" "+%j"
059
(ok, good, that makes sense)

$ date --date "02/29" "+%j"
060
(ok, that makes sense too)

$ date --date "03/01" "+%j"
060
(oh no)

A little testing showed that if I set the year to be leap year, then it
would work as expected.

Is this the expected behavior?

Thanks
TjL