Broken blocks reappear instantly

When I am connected to a multiplayer environment, broken blocks regenerate immediately. I can break them again but the problem reoccurs. I have tried this on 3 different servers, so I suspect that it could be the client/app but I'm not sure.

There was initially concern that the network wasn't adequate, but we are seeing ping times around 50-70ms or better and the problem continues.

One interesting observation is that this seems to happen only when mining underground. For example, when digging into the ground with a pickaxe, many stone and even dirt blocks will reappear while digging. The vast majority of the reappearing blocks are underground stone. I only saw it once above ground and I'm not certain it really happened, and it's very rare with dirt. But, I can dig down through the dirt and when I hit rocks I can reproduce this every time.