Teemo Shrooms dont explode

Just watched this video and recognized that Teemo shroom didn't pop. ( Minute 6:09 ) In my case it happened several times especially when Jayce jumped on me with his hammer. Shroom was straight under him but he could knock me away and leave without popping it. Same with Lucian dash... he flashed onto the shroom and dashed immediately. Shroom didn't pop either. Don't have the replay anymore...unfortunately.