Bear with me as I am pretty new to union politics. I've been working for about 3 months loading semi-trailers on my hub's twilight sort. Everything on this shift is really nice tbh, compared to my experiences on preload. The supervisors are fine, the flow is manageable, etc. Yesterday, someone didn't show up and they cut off the flow to the trailer the dude was supposed to load for about an hour, increasing the volume on my trailer and the worker next to mine's. After that hour, the supervisor opened it up again and started loading it himself for about 2 hours. I went over to the worker next to my trailer on break and we talked about how he's loading the trailer. I told him I want to file a grievance (I did at the time 100%), and he's like "really? I don't think it's that big of a deal man", and apparently he hasn't heard of anyone filing a grievance on anyone in his 2 years of seniority on this shift. But I came from preload, and if I saw a sup do any amount of work on preload I'd file on them ASAP. The culture is different on this sort, still I'm conflicted. I don't have any problems with the supervisor himself, but he still shouldn't have done the work. What would you do?