Quick question on DP Piercing Rounds

[Mack008]

What's the circle that sometimes appears on Piercing Rounds icon?

 

I know I've read it before but can't find it.

[FupDup]

That indication is telling you that its -res debuff is inactive and is thus basically telling you to re-apply it.

[Mack008]

That's... different.

 

Thanks for the answer.