Not seen this mentioned elsewhere, but several times I've seen odd behaviour from Eder's Knock Down ability. Sometimes he does it twice in very quick succession, having spent only one of his two per encounter uses. Other times he is knocking down several enemies at once, even fellow team members. That's not supposed to be possible.

(We got hosed in that fight against the Dweller, but knocking out Pallegina, twice, certainly didn't help matters)

About knock down area of effect, I don't know but if I am to guess maybe it's because you have equipped the larder door and at the moment you have activated the knock down, some enemies hit you and the shield bash applied knock down to them too.

About hitting party member, in the screenshot it's not clear but was Palegina charmed, confused or dominated? If that is the case, then under any of that conditions the party members are treated as enemies by the combat mechanics (for example they are affected by foe area of effects of a chant)

This seems to be a new bug that sprouted up with the recent patches. I see reports on the official forums sprouting up like mushrooms about characters damaging themselves and other party members.

http://forums.obsidian.net/topic/88361-what-happened-character-hit-himself-mechanic/
http://forums.obsidian.net/topic/88374-303-are-there-issues-with-amplified-thrust-andor-take-the-hit/
http://forums.obsidian.net/topic/88092-psychic-backlash-bug-cipher-use-it-on-himself-at-the-begining-of-battle/

I have finally registered over at Obsidian and posted about it there, so hopefully some developer type will take notice, even if they don't post about it in the forum. I suspect it may have something to do with Consecrate ground firing, but it could also be a coincidence.

After I posted about this here, I've also seen enemy skeleton wizards causing mass damage with Necrotic Lance. Like Knock Down, this spell is supposed to target one enemy, but it hit several characters, both friendly and foes. Something is amiss.