When a post is both "watched" and "deleted", the watched styling takes precedence instead of the deleted styling. In my opinion, it should be the other way around (the fact it's deleted is more important than the fact it's watched).
Specifically, a post that has .s-post-summary__deleted and .s-post-summary__watched will have it's background color set to the watched value.
Here is a screenshot showing four posts:
- a deleted post with red background
- a watched & delete post with the yellow background (this is the one I think should be red)
- a watched post with yellow background
- a normal post with neither watched or deleted

Note that the style appears to come from primary.css instead of stacks.css:
