Device: On all devices, this is AI logic bug with Ninja skills

Steps to recreate:

Go to any level of spider den, use Ninja in your team in any position, choose "start on auto", start the fight.

Observe Ninja using Cyan Slash on the boss (big spider), so it deals damage only to boss and not adds as well.

Go to any other dungeon, keep, or campaign, use Ninja in your team in any position, choose "start on auto", start the fight. 

Observe Ninja using Cyan Slash on adds rather than on boss, so it deals damage to both boss and the adds.