For whatever reason, I have a chunk on my singleplayer world, that whenever I quit my world and come back on, it reverts back to a previous state. Imagine that you have a chunk and there are 10 cows on it. You go on your world, kill 8 of the cows and save and quit. You come back later and all 10 cows are back, and any blocks you moved out or placed in the chunk are also back to where they used to be. I may have explained that confusingly, and I apologize for that. I hope you can fix this problem soon!

Thanks!
KRE