Yearly occurrence with dtstart leads to infinite program run

This code in rails console leads to infinite program run in occurrences method.

time = Time.parse("Fri Nov 19 18:00:00 UTC 2010").utc
event = RiCal.Event do

dtstart time
dtend time + 30.minutes
add_rrule "FREQ=YEARLY;BYMONTH=5;BYMONTHDAY=7;INTERVAL=2"

end
event.occurrences(:count => 3).map(&:start_time)

Also I've tried to run this test
https://github.com/rubyredrick/ri_cal/blob/master/spec/ri_cal/inf_l...
but with dtstart property changed from "DTSTART;VALUE=DATE:19400713" to "DTSTART:19701018T000000" in VEVENT section(and DTEND property too), and the result was the same (infinite run).