Actually, I think it is fairly normal to find shafts off by that much weight. Did you spine them as well? You might find that isn't as represented either.
It takes a fair amount of time to weigh and scale every shaft, and a lot of vendors simply don't do it. Unless you have both a grain scale and spine tester, you would be none the wiser for it.
Substantial variances in spine and/or weight are a major reason newbies or folks without these two implements report inconsistent arrow flight when they try wood for the first time. So, they trash wood arrows, when the condemnation should be on the vendor who sells unmatched shafts.
That being said, some vendors really do a good job meeting spine and weight ranges advertised. I'll give a shout out to Surewood, for example. I've purchased a couple of dozen shafts from them over the years, and not a one was outside the parameters I ordered. On top of that, the grain was excellent as well.
Other than Surewoods (and I'm sure there are some other really good vendors as well) I've taken to buying shafts at large shoots where I can hand select and weigh them on site. Still need to confirm the spine on my tester whenI get home.
It's not unreasonable to expect the vendor to replace the three shafts that are way out of line.
All this being said, I've seen very few people who can actually detect a 50 gratin difference in their arrows when they shoot. Within reason, spine is more important than weight.