When attempting to place a block at the height limit, a message is displayed in chat saying 'Height limit for building is 256 blocks'
The message is displayed twice when the block trying to be placed is in the off-hand slot. It does not matter what is in your main hand as long as does not have a right click function. It also does not matter or what your gamemode is, or which block is in your off-hand. A very minor bug, but a bug nonetheless.

The screenshot attached was taken after right clicking on the top face of the block in front of me ONCE with a previously empty chat.