Put the summary of the bug you're having here

What I expected to happen was the blocks to have not disappeared

What actually happened was when I "shift clicked" the blocks into my fully inventory any that did not fit into the stack of 64 were lost.

Steps to Reproduce:
1. Put oak wood planks into your crafting bench to make oak wood slabs.
2. With a full inventory but make sure that the is 63 oak wood slabs so you can only add one block.
3. Try to shift click the 6 oak wood slabs you just made into your inventory and the excess of blocks that do not fit into the stack will disappear .