Feed will hang at after scrolling through ~100 posts

This seems to be related to thumbnails that aren't fully loaded, but not always?

1. When scrolling fast and preventing thumbnails from fully loading, I can get the feed to temporarily hang until it finishes loading loading some thumbnails.
2. I will eventually hit a "feed limit" when scrolling through the feed to ~100 posts.
3. Sometimes, slowly scrolling back up the feed to allow unloaded thumbnails to finish may "unblock" the feed for a bit, but not always. It may load one or two additional posts, and hang again.

There seem to be multiple conditions causing the feed to pause vs completely hang, and I can't nail those conditions down.

This issue has gotten much better since 219, but is still a bit quirky.