There are many multiplayer bugs I find while my time player on a lan server with 2 people.

There are millions bugs on the lan server, I will just list a few: when hoeing, it might give you spruce tree sapling instead of seeds, random things pop up on uploaded chucks, left side ways spruce log crashes sever, placing down seeds in hoed soil might change the seed into a sapling, furnace might not open... etc..