Having left the app for several hours after viewing a question, re-launching it reloaded the question I'd been viewing. Upon tapping back, the Achievements icon in the top-right had shifted down a bit. I took a screenshot, then refreshed the view, which then showed I had reputation changes.
Most likely, the icon was updated with the reputation change before closing the app. Upon restoring the view the +10
was forgotten but the icon shift was not.