I was playing Minecraft with my family but suddenly there is a massive missing or deleted chunk in my sister's map but my sister doesn't see it and she don't fall from the void but only me i can see a deleted chunks and fall from the void weird and that happens in my own downloaded map when im playing Minecraft with no one this thing happens this is my worst nightmare ever. When i connect to my friend's map the chunk began to disappear after 2 nights in minecraft but sometimes nothing happened at all please fix this massive bug.

2 short bugs:
1.my skinpack does not load
2.when opening my minecraft it takes 5 minutes to open.