Six- and five-Gina's moon jellies (?)

Most of these jellies had 4 gonads (if I remember my undergrad invert class correctly) - the horseshoe shapes in the middle of the bell. But, there were a number of jellies that had 6 gonads, and a few that had 5. Is this normal diversity? Or something else causing this anomaly? There was a "swarm" of many jellies of all sizes right at surface near public docks on Quadra Island, B.C., Canada.