You're talking about that thin metal disk with the hole in it? That's just how some SK sockets are finished. There have been numerous threads about the interior finish of SK sockets. You're used to looking through the socket from top to bottom expecting to see through the square drive on the other side but, sometimes it doesn't work that way with SK sockets. It doesn't affect the socket's performance but, can irk the purchaser.
Where have others complained about this? I've seen complaints about the interior finish being painted silver or being dull chrome, but the issue with these is that the metal disk in the middle hasn't been punched out. All of my SK (ideal) sockets have that part removed.
As far as I know, SK (or any company) has never intentionally produced sockets like that. That metal disk should have been removed in the forging process for sockets this small. The larger SK sockets (24MM+) have that metal disc split into 6 pieces and have them pressed down and out of the way so that a rod could pass into the socket a bit if needed. They never should have been left solid so that objects can't pass through them.
Furthermore, by looking at the plastic socket holder rail, you got old stock sockets (from before Ideal bought). Call up the new SK and talk to them, or use them as they are.
Here is a picture showing the two styles of SK broaching. These are normal. What the OP has is not, and was certainly produced during the SK bankruptcy era (going by the socket rail in the pictures).