Board Thread:Bug Reports/@comment-26427728-20170727235621/@comment-25101089-20170729152625

SamwiseFilmore wrote: Granted. Buy why is it trying to access the 46'th slot?

From what I can tell, this bug was caused by a mismatch between the player's open container on the server, and that on the client. The server had a bookshelf container open (with 54 slots) while the client had the normal inventory. Then, when the server tries to send the contents of the 46th slot to the player, Crash!

As to why there was a mismatch? I think that was because, sometimes, the bookshelf block wasn't updated to the new 'storage bookshelf' block on the client side. Which was simple enough to fix - the hard part was determining the actual cause.