/clear <player> <item id> Not functioning as expected

When attaching a comparator to a command block which has the command "/clear <player> <item id>", the comparator will return true, even if the item in question is not removed from the players inventory.

I expected it to not output a redstone signal at all if there were no items removed. However it appears that the only way for that to happen is for that player to not exist on the server