Leader of the Pack effect

[Haenir]

The swarm pet proc from this item is a self-targeted detrimental and is resistible -- leading to the item being less useful the more magic resist you have (i.e., over about 350 MR you don't actually proc any rats). Is this working as intended?

Compare Monster Summoning -- unresistible to Summon Yclist Rat -- resistible

 

[Rarok]

The swarm pet proc from this item is a self-targeted detrimental and is resistible -- leading to the item being less useful the more magic resist you have (i.e., over about 350 MR you don't actually proc any rats). Is this working as intended?

Compare Monster Summoning -- unresistible to Summon Yclist Rat -- resistible

You can pretty much assume it was an oversight. A beneficial summon being resisted by the person it is going to help is a mistake. Nice catch!