I was playing survival and noticed this weird bug, when breaking sugar cane on a dirt block if you keep holding the left mouse button and let go before the dirt block is broken the amount the dirt block has been broken gets saved where it is until it is updated again. 

The video file is too big for the attachment section so here is a link to an unlisted youtube video: https://www.youtube.com/watch?v=wkomJDdqc7c