This Bug seems to be always repeatable. Create an event with a start time prior to the 1st of January 1970 and set its recurrence frequency to once a year. The event will not be shown on the same day the next or any following year.
Yes, Orage is not able to go older than 1970. This is basically due to linux time() limitation, which has not been worked around in Orage: $ man 2 time ..... DESCRIPTION time() returns the time since the Epoch (00:00:00 UTC, January 1, 1970), measured in seconds. ..... If you use a bit older dates, you will see that those jump (like 1960 to 2060 etc).