Yes, those are not down clusters. Those are immature feathers, possibly breast feathers or downy intermediate feathers. As Greg shows in his pic, down plumes do NOT have a prevalent “stalk.”
Basically, the denser the weave, the less there is a problem with escapees. Lighter fabrics often do not pack threads as densely as heavier threads. (There are mechanical reasons for this.) My EE quilt bleeds an occasional feather through 10D fabric. I would guess 7D is even worse about this. However, in this case, it looks like the stitching was possibly performed using an improperly sized needle. A smaller needle would have helped some, I think. But in any case, likely this is not the problem. As was said, “pin” feathers can escape, down, not so much.
I also have a 10D jacket that bleeds an occasional feather through the seams. No, I tried a bit of seam sealer, and it seemed to help, but I am afraid it also matted down the down in that area (cuffs.) Not really a good trade-off. It is also about 10-15 years old.
In any case, it appears to be more of a down quality issue than a fabric issue. The large number of immature feathers in your pics doesn’t seem right for an 800FP down. It looks more like a lower fill down as was said. If this is the first one or two uses, you will get a few, but covered enough to complain about? Your pics show enough loose feathers that I would be uncomfortable sleeping in it from all the little pricks and pokes.
A low fill power down coupled with a UL fabric can do that. One of those cases where lightweight down lets you use lightweight materials, making the overall weight very light. Lower fill downs often needs heavier material leaving the overall weight higher.
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