I submitted a ticket to 2K and received this informative response. (Complex Root is working as intended and can/will kill Moze when used with specific skills and perks). Be careful .
“Thank you for contacting us! I understand your concerns regarding the Complex Root and Area-of-Effect skills/gears boosting the Splash Damage’s size. However, this is not precisely a bug, but an intended feature: Torgue Cross-Promotion and gear that increases Splash radius directly affects the Complex Root’s effect, as this damage is counted as splash damage (FYI; please be careful with it as it may hurt teammates!)
You would be able to hit several enemies and boost splash damage with Moze’s abilities, however, Splash radius (if close enough) can affect you, the same as other Splash Damage weapons such as The Lob, The Scourge or The Kaoson.