Monks are getting incorrectly marked for being able to collect Warglaives. This is for both quest rewards as well as loot form raids. As an example; Glaive of the Keepers is showing up for my windwalker monk:
https://i.gyazo.com/096d57249ac522a1d2ffecaab1026c4b.png

Warglaives (outside of Warglaives of Azinoth and maybe a few Vanilla items) are only obtainable by Demon Hunters.

Go to the 3rd tab (Mini List) and click on "Class Defaults" and it should look like below:

It's possible that in one version it was turned on by accident and was corrected afterwards. So by hitting "Class Defaults" it'll reset it. We could force this on an update, but if we did that it would reset every single setting and we'd rather not do that to anyone. It's similar to how Demon Hunters use to be able to use Daggers, but can't now.