Also just noticed that the very top post in a feed goes ‘dim’ as if it’s marked as read when scrolled off the top of the view, but then pull to refresh reloads it as unread. Opening the post to mark as read and then refreshing hides it as expected (I have hide read enabled).
So this a side effect of some network optimization. In order to not spam the api with hundreds of calls while scrolling, I batch them and send one request for every 10 posts scrolled. When leaving the feed such as opening a post, or changing tabs, the batched posts are processed and the posts are marked read. I neglected to include this behavior when refreshing the feed. I’ll fix this in the next update.