[Last Saturday when I chambered a round, a second round inserted underneath the elevator plate.]
It will most likely recur.

That mis-direction/misfeed can sometimes occur with a slightly different-sized cartridge, but a common wear point for the Winchester 94 is the tip of the cartridge stop - integral to the bottom link - which allows the next shell in the mag to exit while the carrier/elevator is raised.
The fix is to either replace the lower link, or extend the tip of the stop via peening/swadging or a weld buildup.dressdown.
.