[PBE] Nasus and New Devourer Item (Not Entirely Sure If Bug)

So, I saw the new Devourer item and thought I'd try it out, after figuring out what happens after 30, I immediately tried it on Nasus, seeing as it makes ALL on-hit effects hit twice. This apparently isn't the case for Nasus, and I'm not sure if it's the case for other spell activated on-hits like his (thing Garen, Darius, or maybe even Ekko( I have not tested with them, these are just examples of similar abilities)) I made sure to double check, using Q with and without the items passive, and got the same damage, so obviously his Q is NOT being applied twice. Is this intentional or am I not understanding something? Because as far as I know, his Q DOES count as an on-hit and it does say ON-HITS.

I'm not saying by any means it should be, because that's absolutely ridiculous and I don't want a Nasus doing 2,000 damage with a q in 24 minutes but at the same time, it's not stated and I am very curious.