I've noticed the same thing on occasion. Exact same order, too.

When this happened to me, I would select to hide read post and mark scrolled post as read - but eventually I just started using a different app.

For what its worth I had this issue on Fennec as well, so I dont know if its an API issue or an issue on the application side of things.

Hope it gets fixed soon!

Yes, this has happened to me a few times

I saw it once, reloaded and it hasn't happened since.