just to contribute my experience... I also had poor germination this spring, and the seeds weren't from harding but another vendor that has been very reliable in the past. Won't mention the name, because I'm not sure it was their fault.
I used several different planting methods: seed drill, rake/scatter, bed with a roll seed planter, and hand plant in planters. Pretty much got the same dismal results no matter how they were planted. Last year, when I tested seed in some long narrow planters, I got 100% germination. This year, I got maybe 5-10%. OTOH, the 2YO roots I bought in bulk have done very well, so it's probably not the locale.
Didn't save any so I don't have any to crack open, but I strongly suspect that with this many reports of dubious seeds from different vendors, something environmental may have been going on, could have affected the stratification process. This is a persnickety little plant.
Or, they were all getting bulk seeds from the same bad source.
Going to be checking closely next fall. At least I can take heart in knowing that it may not have been something I did wrong.