[GAMEPLAY] Galio's W DoT Bug

I made a report earlier about how Galio's Bulkwark (W) does not proc off of Cassiopeia's poison (I.E. there was NO healing while poisoned, despite the fact that taking damage is supposed to proc his W). I began to notice that his W wasn't working with other champion DoT's (Fizz, brand, Darius, etc.) so I tested out his w against all champion DoTs that I could think of and it just didn't work. It DOES work with Liandry's Torment, but not any DoT's from a champion's ability/passive.