year view tooltip not displaying

Hi,
I’m using the scheduler in year view ‘mode’ ONLY.
My problem is that if I add an event that recurs (only ever yearly) past the end of the month (i.e. from 31st May to 1st June) the tooltip will display for the 31st of May but not display for the first of June.
It shows the “dhx_year_tooltip” class as a thin grey line but does not append the"dhx_tooltip_line" class/es
If I add an event that does not recur for the same dates the tooltip will display correctly.