A command that changes block data, such as:

/blockdata 325 72 231 {Command:/say Bam!}

OR

/setblock -1 3 -8 minecraft:command_block 0 replace {Command:/time add 16}

As well as commands that place blocks do not operate outside of the Worldborder.

[To clarify, when the cords being targeted are outside of the Worldborder]

THIS MAY BE INTENDED ORIGINALLY, HOWEVER:

Many custom maps use systems of redstone and commandblocks at map spawn to make things work, to reduce lag, the players are moved from map spawn so that the "system" is only loaded for the server. Many custom maps will want to move the World border to keep the player within a certain area BUT having the map spawn outside of the Worldborder will cause may of the more advanced systems from working.

If the decision is that we don't want to allow blocks to be placed outside of the border, it would still be easy to find workarounds for many of these systems if we could still use the /blockdata command.