}}} Have you pulled them out and looked at the wires?

It could be that 2A is fed by a different line.
There is a little tab that can be broken off to separate the A from the B.
{{{

You're right. I pulled the outlet on one side of the wall. I found the
dual sockets were independent of each other, electrically. And, there were
two red wires on one side, and two white wires on the other.

At that point, I called an electrician to come sort it out.

Don't know what he'll find about the outlet on the opposite side of the
wall.