Did they replace the bearing as well. My thought is this. If it's leaking out the bearing has to be bad b/c it has to get past the seal on the bearing to be visible. Could be a bad bearing which as stated caused some damage to the seal seating surface. Had this happen to me and my seal only lasted 2 days before leaking again. Bent shafts are a shot but I wouldn't go for the bent shaft issue just yet I'd swap my tires and rims around first and check for tire wobble w/ the truck on jackstands. I have one currently bent so bad you can't get the bearing off of it ( well if I put it in a big honkin press I could) but it's been 6 months and no leaks yet. I'm leaning more towards scoring or such on the seal sruface right inside the axle housing behind the wheel bearing