Some events appearing twice

We have an event that is appearing twice, one of the links is broken.

The correct link is:

…/events/pilates-class-wednesday-2-30/

But there’s a duplicated link:

…/?post_type=page&p=381

This duplicated link doesn’t work but has the same name and time.

This is happening on another event too.

Other than that, all events in the future seem to be okay.

I’ve included the link to the page in this support request.

Thanks,

The page I need help with: [log in to see the link]