Can't edit keynote because it needs an update that doesn't appear on my App Store

I created a Keynote presentation and shared it for collaboration with my designer. We were working just fine since Monday until a few hours ago. Everytime I open the presentation, there's an exclamation mark on the collab icon and a sign pops up telling me there's a Keynote update available. However, when I go to the App Store, there's nothing to update.

I already checked on the system preferences for new updates and even updated my Mac to the latest version (macOS Mojave 10.14.4).