for me it worked by replacing in line 129:

new Date().getFullYear()

with

new Date(parseInt(event.startDate)).getFullYear()

@chamaeleon82 Same here. There is a logical bug in the calculation of “yearDiff” in calendar.js line 129-130. It calculates “CurrentYear” - “FirstYear of event” instead “NextOccurrenceYear of event” - “FirstYear of event”. I’m not too familiar with js, but the fix should be something like yearDiff = event.startDate.getFullYear() - event.firstYear.