Ret Azerite trait error?

Ok I dont know if this is an error or not but Im getting suggested to use a piece of azerite armor that gives mastery on the 1st trait. ( Breastplate of Rezan’s Bladeguard )

This, combined with my mastery amount turns into reorigination array to turn into mastery instead of haste. I have run simulations and it still shows bigger dps with rezans bladeguard instead of other pieces of same ilvl gear with non mastery traits.

is this real or a bug in the suggestion?..

If you post your addon export we can take a look. Hard for me to say without seeing the whole picture.