GA Activating Inside Terrain.. lmao

i experienced this bug whilst I was playing riven. Its pretty coincidental actually. I was playing riven with GA, and was being chased by the enemy ADC. I was on like 10HP. I stopped to press the red jungle bomb plant (the one that flings you over the terrain) - Their ADC aa'd be like right before I clicked it. I managed to get airborn, however their AA was chasing me. Basically, Whilst I was mid-air, the AA got me and I died. I fell literally inside the terrain and GA activated. After I revived from GA, I was like invulnerable inside the terrain for 3 seconds, before being shot out of the terrain onto the enemy (back where the plant was)

pretty weird.