Is it possible to run an 8-wire ethernet cable to 2 RJ-45 sockets in parallel?

Question

Cables and wires

NOT 4 cores per socket, and exactly 8 cores, what will happen?

Answer 1

what will happen?

Nothing terrible will happen if you then stick the patch cord into only one outlet. Well, the signal at the physical level will deteriorate a little, but most likely it will not affect the data transfer in any way. If you connect two devices to these two sockets, then it simply will not work and that's it. Pull out one device - it will work again.
All of the above - IMHO, because. few people are interested in testing this in practice.
Upd. the passive hub should contain a bunch of resistors .