Good catch. This is actually further problematic because Toughness is supposed to grant immunity to an attack. Loner is not an attack, nor is Ouch, nor is Blind Rage, Demonic Revenge, etc.
This has been discussed a few times already. Toughness doesn't act as armor in all cases. Bug or not, idk.
Thinking about it more, Toughness probably needs to say "to any one damage source" since it also applies to terrain and attachments. EDIT: Done. Not sure about the armor/psychic interaction though.
I would be curious to test whether Demonic Feedback is stopped by Toughness. I recall that it isn't prevented by Impenetrable Nimbus.
New wording helps, of course as you note the original comment about competing armor vs. not preventable by armor still should be tweaked somehow. *The two cards that I can think of in play here are Loner and Blind Rage which both currently trigger Toughness but their wording makes it seem like they shouldn't. All "unpreventable" damage types (demonic feedback/power/revenge), do not trigger toughness.
