On Summer '20, but don't see Split Views in production

My production org roller to Summer '20 this weekend, and I was looking forward to getting the standard app Split View option out to my team. I can verify all the other features, I know it's on Summer, but Apps do not have the split view option in List Views.

My full sandbox has been on summer '20 for a few weeks and *does* have the split view on same Apps and Objects, but I can't figure out where I may need to enable this.

https://releasenotes.docs.salesforce.com/en-us/summer20/release-notes/rn_lex_split_view.htm

The App in question has the objects in the nav, which is one requirement I see. Any tips, something else to look into?