Sticky side bar is suddenly not sticky

Sticky side bar is suddenly not sticky.

Well… not suddenly. It happened after I made some changes to the page layout.

I’ve been trying to clean up one of our CMS Collection template pages because it was terribly laid out (originally designed by me: a not-designer). BUT, for all its faults, it had a well functioning sticky left hand side bar.

After my clean up, the page is more neatly laid out, hooray.
But somewhere in the change, the side bar is no longer acting sticky. I can’t work out why it won’t work anymore.

I’ve done all the basic troubleshooting.
I’ve set a sticky position height.
None of the parents have overflow set to hidden.
The parent containers have a defined height (I think!).

I have even cloned other Webflow sites with sticky side bars and tried to rebuild. Those sidebars are sticky! Wow!
But then, once I paste all of my actual sidebar content in, they are suddenly not sticky again.

It’s so confusing. I’m not sure what I am doing wrong.

If anyone has advice for this not-designer, I’d be very grateful!

A real life example of the CMS collection page here: Bounce Playgroup
Read-Only version of the site here: Webflow - CCIW
The problem is in the CMS Collection page: “Events and Ministry Pages Template”

Here is my site Read-Only: Webflow - CCIW