I have the preferences set to not show read posts, but still see posts in my feed (shown grayed out) that have been hidden. I think they are posts from another instance that is federated (like maybe I hid them on the other instance). Is hide (the checkmark) not the same as mark as read? And, even if not, shouldn’t a hidden post stay hidden? If it is greyed out, the app knows it has been seen (or marked).
Edit: Lemmy bug: https://github.com/LemmyNet/lemmy/issues/4290
I think I know what is going on. Do you have more than one account added to Boost? The app marks posts as read locally too, maybe it was read with the other account.
I will fix that.