I found a bug in rumble tonight. I used the grappling hook to hit a ball as it was frozen.. my car then got stuck in air while the rope went out but it didn't complete the cycle. I played for a minute or so while I had the grappling hook symbol on my screen and not going to another powerup. When I finally hit R it used the powerup like it was on the whole time. (1:10 into the video) It used the powerup without any other sign of having said powerup. I didn't get it recorded as my video drivers needed updating at the time, but the video shows how I was stuck and using the powerup without any indication of using a powerup.