Issue overview:

Inputting a /setblock or /fill command that has its y parameter between y=-1 and y=-64 sometimes returns an error reading "Cannot place block outside of the world".

Reproducing the issue:

While I have experienced this error on several occasions, it is inconsistent to reproduce.

The most reliable way to reproduce the error is to attempt to place a block using the setblock or fill commands either by hand or with a command block, so long as the any of the y parameters are less than 0 but greater than -64.

Additional Notes:

The issue can sometimes be resolved by replacing the command block.