Certain blocks changing between saves

I have noticed certain blocks converting to different blocks in between saves. First I had a row of carrots and wheat crops growing and when I reloaded I had noticed they all turned to wheat crops. The most recent instance of conversion was my rabbit entity crammer. The space with a dispenser had turned to air, the rabbits disappeared entirely an the air block above their cage covered itself with a grass block. Oh and the button and single fence post disappeared too.