Minecarts glitch and now I cannot stop breaking blocks

I credit my son for finding this bug... He runs into this problem constantly whenever playing with minecarts and tracks. He gets stuck in a mode where his character gets perma-stuck breaking blocks. We aren't even touching the screen.

We are on a Surface 4, using the touch screen split controls. (Also repro's on my Nexus 7 tablet).

Here is what we are typically doing:

1. Create a new world in creative mode.
2. Lay down some minecart tracks (we usually have like 20). Unsure if you need to mix powered rails and regular rails.
3. Place a minecart on the tracks.
4. Ride the cart.
5. Get out of the cart.
6. Build some more rails? Run some carts off the edge?
7. Ride the cart.
8. Get out of the cart.

Sometimes, the minecart starts rocking very fast side to side. I try to break it and remove it, but instead of breaking the cart, my character hops in for a ride (I did not tap the ride button). I can hop back out OK.

After this point, my character will start breaking any blocks within reach, as soon as I look at them. I've tried flying out of range of a block and then coming back, but the character still breaks blocks on his own whenever I get back in reach.

I hope you can help, so my son can play with minecarts again!