HitTargetOnly doesn't work on mobs

Summary

A missile is fired from a mob to the boss that grants the boss some buffs. However,other mobs can block the missile and get the buff instead of the boss. Pastebin of the skill used: https://pastebin.pl/view/ca3fffc4

Steps to reproduce

• 1- Put a mob between the caster and target (in case,the boss)
• 2- Trigger the skill. The missile will hit the other mob instead of the boss

Current behavior

The missile can hit any mob,not just the boss

Intended correct behavior

The missile is supposed to target no one (including other mobs) but the boss

Server log file

https://pastebin.pl/view/48600800

Debug log snippet

https://pastebin.pl/view/f214600f

Proposed fixes

The boss is probably not considered as "a target" for HitTargetOnly. I have to enable the missile to not hit players and hit mobs instead in order for the missile to actually register the boss as a target so that may be the problem too