As the title says, I realized this in my Nightblade character which I use Power Extraction on. I get the Major Brutality and Major Sorcery buff from Power Extraction and then if a groupmate casts Igneous Weapons the duration of Major Sorcery buff refreshes and becomes longer as it is in Igneous weapons but not Major Brutality. I am checking this on both buffs bar and character page, and I dont use any add-ons that affects both buff bar and character page.