Can’t link to custom posts in block editor

When I create a blog post using the new editor, I am not able to link to any of my custom posts.

Steps to recreate:
1) Highlight the word(s) I want to link,
2) Click the link button
3) Search for the title of one of my custom posts

I expect: that post to be returned so I can click on it to link it.

Instead, only my existing posts and pages appear in the link search results, not any of my custom posts.