In my opinion, it is hard to see in that picture whether or not any of the lacquer did run down into the pocket. I am not saying it did - I am saying I can’t tell because the picture was taken so perfection straight on. However, one thing I didn’t know and seems apparent - maybe I am wrong - and that is that the primer crimps seem to be applied AFTER the sealant, at least in this factory. I have not gone downstairs to look at lots of 7.9s to see if it is always so, but it sure looks that way for this box. Interesting.
It is a wonder than no one involved in the inspection and boxing process of this ammo caught this. I think most ammo was boxed by hand then - I have seen pictures of people - mostly women - doing this at various factories in various countries. The Germans were fairly technologically advanced, so maybe that had machine packing. Again, I don’t know. Still, it does happen today. In years of looking at ammo new in boxes both as a shooter and a collector and in showing thousands of boxes over the years to customers, I have found one round with no primer and sever with the primer either seated backwards or crushed into the pocket sideways, all going undetected. By the amount of rounds looked at, the number didn’t amount to a pimple on an elphants back-side, however, just as someone else pointed out on this thread.