I tried the “merge duplicates” action on the settings page, but it seems to still be an issue. I am importing them from facebook automatically via your facebook plugin. Thanks.
It looks like you’ve stumbled across a known bug (https://theeventscalendar.com/bug-hunting/). You can find the original thread and the discussion here https://tri.be/support/forums/topic/events-importing-multiple-times/. I don’t have an ETA for when a maintenance patch might be released, but we are working on getting this fixed. Some users have reported some success with changing the frequency of imports to a longer time period. Worth a try perhaps?
Sorry we don’t have a better answer for you at this time.
For now I am just linking the menu item to our Facebook events page, but ideally we’d like it to look the same as the rest of our site. Please let me know when this is fixed, hopefully soon.