Episode Posters vs Thumbnails

I recently added poster artwork to the individual episodes of a few TV series.  In the skin I use most frequently (Estuary MODv2), everything works fine.  Thumbnails show up where they should and posters are used properly.  However, when I’m in the base Estuary skin (or syncing my library with Yatse Remote), the poster artwork seems to supersede the thumbnail artwork for the episodes.  For instance, if I’m looking at the season of a show, all episodes with only thumbnails show up correctly, but any episodes that have both a poster and a thumbnail show a cropped image of the poster instead of the available thumbnail.  Here’s an example:
You can see that Episodes 1, 3, and 4, for example, use the thumbnail image because it has no poster, while episodes 2 and 5, which have a poster, crops that instead of showing the thumbnail.  Here is the available artwork of Episode 2, showing the thumbnail is still there correctly:
I know Estuary does not support Episode poster artwork.  That’s fine.  I would just expect the behavior to be to always choose the correct thumbnail artwork for display and just completely ignore any extra associated artwork.  Is there a setting I’m missing to get it to prioritize the thumbnail artwork when necessary?

Not sure if this should be in the Estuary Skin discussion instead of here, but I figure since it affects Yatse as well it might be more than just a skin issue.  Feel free to move if necessary.