While leveling in Threads of Fate you get gear such as Corpsehide Helm which is level and ilvl appropriate. AMR sees the correct ilvl and the correct stats but thinks it requires level 60 and so it skips it for optimization.
Blizzard changed how they are modifying the required item level… it’s actually quite difficult to figure out now.
I fixed an issue earlier today where crafted gear wasn’t getting the proper required level – they added a new type of bonus ID that sets it to an item level.
That item you mention, it has a required level of 60 on the base item, but then there is no bonus ID information to reduce that required level… so we’ll have to guess at what they intend I suppose. It seems in this case they are implicitly reducing the required level to your player level when you obtained the item, but they don’t do the same thing with crafted gear (which also has the same information about your player level when it dropped).
We’ll try to figure it out in the next update – I wish Blizzard would pick one way to do it and stick with it!
I posted an update that should resolve most of these issues with the required level not getting imported correctly. You will need re-import your character from the addon for the items to update.