Ideas
I'm playing on Xbox atm and not tech savy enough to tranfer a screenshot, there is nothing to see that would be helpful however as the Holiday UI just goes and event Icon remains. Holidays work correctly now I've completed the current event tasks but this is frustrating as it means I'll have to do the events tasks straight away so my game can fuction normally again. I'm presuming that whoever is in charge of event tasks has used similar coding as seasons holidays and when an event is in progress it messes with the UI. Just a guess.
CommodoreLezmo still bit unsure what you are seeing but you can usually switch between holidays and the event tasks.
I'll take a screenshot tomorrow when the next tasks appear.
It could however be a console issue only. There have been other reports of other events not working properly which I can't duplicate .