Some blocks after you break them and save the game a bit later, it pops up again in the same place when you open up the world again

Placed down some item frame with maps and broke a mossy fence and killed a baby zombie, a saved it after placing down some cobble and breaking some stone in other places.

When I re-opened it, the item frames were gone, the mossy fence came back, and the baby zombie is revived...

after I Placed down some item frame with maps and broke a mossy fence and killed a baby zombie again and saved it

they were back again when I opened the world...

Fixed when I went back to 1.6.2