I don't think the hair will be cursed, since you already paid a high price to get it (very difficult battle (before you realize you can cheese it with magic missile and hex/ witch bolt), and you can not just kill her, but must be very careful to leave her at low health, extending the battle and exposing yourself to more damage), but I believe that the mark of the absolute will have such a function.
Right now, the absolutes warboard is probably the strongest item in the game, and the gloves of power are also very ... powerful. And you get the mark for free without any struggle.
When we fight the absolute/ other cultists in moonrise towers, I suspect the cultists will be able to debuff us with bane instead if we have the mark, or maybe dominate us sometimes (with a saving throw each turn) like Ethel with the whispering mask
