I encountered a bug when I start to mine a block an image of the squid template will pop up on the block briefly before finishing mining the block. As I know of the issue seems to affect all blocks. The process I believe caused it goes as follows: I created a backup of my hardcore world by going into the files copying the save and turning it into a zip and moved it to the backups folder. I eventually died on the original save and so I extracted the backup zip file into the saves folder and it prompted me to replace the original files, which I did. I then proceeded back to Minecraft and noticed the bug. This bug didn't happen previously in the original save, only when I replaced it with the backup. I assume it directly came from me replacing the files of the original and it must have messed up in the process resulting in the bug.