Pop corn buds are my biggest pet peeve. I used to get them all the time. I also grow one plant to one 55w autocob..The reason for pop corn buds, is just grow style.. I used to let my plants grow naturally.. Now I'm like, screw that, lol. As soon as the stretch ends, I "lollipop" the plant. I pull off all of the lower nodes on the side branches. Those lower nodes are what turn into popcorn buds/larf. i aslo do it again at the start of flower. Remember, that all through veg, the main cola and all of the branches have been competing to be the tallest and closest to the light. Who ever wins, gets most of the plants energy (that's why people want an "even canopy"). The plant puts very little effort into those lower popcorn buds. Some pop corn buds dont even finish, so I get rid of them early.
Everyone who commented is right about your current plant still needing time though, but as far as popcorn buds go, you have to eliminate them early on.