013-0098-02 is the same: only five pins. The emitter sockets on the curve tracer
should be permanently tied together (regardless of the position of the selector
switch), so two emitter pins are not needed on the adapter.
Perhaps there is a wiring fault in your 576 standard test fixture? Or there may
be a wiring fault in your -02 adapter. I have a 577/177, and can confirm that the
emitter sockets are shorted.
I don't have a 576, but the service manual shows the two sockets being shorted
there as well.