If you try to remove a tile entity (e.g. a sign, a chest,...) with /setblock <x y z> air it says "The block couldn't be placed". Only the error message appears, the command works fine and removes the tile entity. /fill don't gives the error message.
If you replace a tile entity with any other block than air, the error message doesn't appear either.

This might be related to MC-77033 and MC-82703