Note: I posted this in the Bug Report section of the US forum. As it occurred on the EU server, I decided to post it here as well. (If the bug report in the US forum is sufficient, feel free to delete this.)
I had a bug in Arena, where the armor wouldn’t show. I played as warrior. Everything worked fine. Then, in the later stage of the game, I was at 2 health (with no armor). I played Garrosh’s Gift to get a temporary copy of Shield Block. I played it. It drew a card, but my health stayed at two with no armor. Next turn, my opponent attacked me with a 3-attack-weapon, but my health stayed at 2. So the armor was correctly added, it just didn’t show. From that point on, everytime I gained armor, it just wouldn’t show, and I stayed at 2 health with no armor shown for the rest of the game.
I don’t know, if that’s a general bug or a Shield Block bug, or probably it just has something to do with the temporary copy of Shield Block from Garrosh’s Gift. It was the first time I’ve chosen Shield Block from the discover, and it should be the least picked option. Therefore, maybe the bug hasn’t been noticed, yet.
I also have a screen captured video of the bug, if that helps. (It just shows me pressing the hero power button with no visible change of armor.)