Condition in lookup field causes results to disappear

I have a custom object called "Site Visit". It has a checkbox field called "Closed".

I created a lookup field for tickets called "Site Visit" that looks up the custom object.

If I have the condition "Closed is unchecked", the results are empty.

 

But with no conditions, I see them without issue.

 

You can see that I have the field checked on one object, and unchecked on the other. So Visit 2 should show. But it doesn't, even if I search for it.

What gives?