The timers on the proxy body parts do not seem to be right. The items list "Lifespan: XXXX seconds" in the description when you hover over them. I believe it started out at 10800, or somewhere near three hours essentially when you break it down that way. The number is decreasing every minute and only decreasing by 10 every minute.
The items will have 6x the lifespan as intended if seconds are indeed the correct increment for the timer.
I have not tested if the body parts will still work for the quest to see if maybe the display timer is the only thing wrong as I don't have the time today.