Singed Q turning off. (Game Play)

Just finished a game as Singed. I was laned vs an Sion. Every time he used an ability on me, my Q would turn off. My ability bar wasn't showing the flashing around the Q, nor did I see a poison trail. As the game went on it was happening from other champions that were attacking me. Someone said they saw the trail still, yet I didn't see it nor was my Q on (due to turning off).

   One of the other team said they saw it, weren't slowed from it at all ( had Rylai's Crystal Scepter) so I don't know what they were seeing since my team and the rest of the other team didn't see it on.

    I don't have quick cast on. I wasn't turning off my Q, to the point where I would remove my key so I wouldn't fat finger it and turn it off after I turned it on.

Other champs attacking me as Singed

Morgana Sivir Volibear leblanc Match history. http://matchhistory.na.leagueoflegends.com/en/#match-details/NA1/1677731383/42996135?tab=overview