Adding CMS collections to tabs

Is it possible to display content from 1 collection list on one tab and another collection list in another?

I’m trying to show upcoming vs. past events on a profile page, but when I added the second collection list, it deleted the first and replaced the data.

You can have up to 20 collection lists per page, and there are no restrictions on using them inside of a tab element.

Not sure what you did and you didn’t share your site readonly link, but you shouldn’t have any problems here.