Adding a filter to a view “or” remove results?

Question

I've got a view that is trying to show three different content types (Lesson, Drill, Exercise), each with three different flags(Lesson Flag, Drill Flag, Exercise Flag), each of those flags have 3 fields (Review Date, Review Date, Lesson Status). I only want to display items that have a flag with REVIEW date <= today, OR learning status of Incomplete. But when I add the OR condition that the flags learning status = incomplete, all of the results of the other two content types are removed. (IE, before adding the filter I have 7 items, after adding the filter the view only shows one item that wasn't there before)

This seems to defy my understanding of how the "or" condition works, and I'm curious why this would happen.

Here's a picture with the filters I have set up:

Is there something I'm not understanding about how the OR condition works? Or an existing bugs in views 7x.3x that causes them to behave badly?

Answer 1

I figured this out. In order to prevent this behavior, I had to check "reduce duplicates" in the filter, as well as remove some "required relationships.