When using Blood DK, there is no option to uncheck multiple target. The option exists for Frost and Unholy, but the setting does not carry over to Blood.

Vengeance DH is the same, FYI. Seems to be a tank thing, Haven't checked my Bear Tank.

Yes, those are the scripts I contributed as they don't exist in simcraft T18.
Protection Paladin will also show this behavior.

Guardian Druid, Protection Warrior and BrewMaster don't have any scripts defined so they won't have the issue :)