Loud sound in air pro 4 when using noise cancellation on bus

I got my air pro 4's a couple of weeks ago and they have been great. However, when I am riding the bus with noise cancellation on, the earbuds make a loud popping/crunching/thumping sound whenever the bus hits a bump in the road. It seems like the noise cancellation is trying to cancel out the noise of the bus hitting a bump and making a loud sound. It's quite annoying and I was wondering if anyone else has run into this issue? Or if this is something that could be fixed with a firmware update? I haven't had this issue with any other noise cancelling devices in the past.