When you place a Shroom very close to a ward, the shroom will be triggered if the ward expires or is destroyed. To recreate this bug, place a shroom next to a ward and either wait for the ward's timer to expire or sweep the ward. I did not test this with vision wards, but it happens very consistently with trinket green wards.
I second this. Just finished playing a game, was jungle teemo and trying to do my best to shroom the entire world however any time there was a green OR pink ward that expired or was killed it would kill the shroom. There was also some text that I saw appear now and then however it was at the corner of the screen so I can't confirm what it said. Definitely need to look into this.
The text says "invulnerable".
