Version: 8.1.3

Since 8.1 I appear to be having issues with item counts, maybe only for conjured items though possibly other items.
Known affected items:

• Mystical Flask (from Cauldron)
• Healthstone

If I use these items, the action button does not update, and sometimes the update is so delayed that I go into combat thinking I have a healthstone but I actually ran out of charges last fight!

I've not reproduced this one.

Yeah it turns out it's a bug on Blizzard's end. There's a huge forum thread regarding it.