This isn't a bug. The automaton's ranged attacks (and barrage) are treated the same as weapon skills or job abilities.

When a player uses a ranged attack, you see
"Player's ranged attack hits the mob for x damage."
When the auto uses a ranged attack, you see
"Auto uses Ranged Attack.
Target takes X damage."
e.g. the same as any weapon skill or damage-dealing job ability (which also give ruby).