What's your watering schedule like? Looks like they might be getting too much water. If not, then I wouldn't sweat it. I've had plants do that before for little things like cloning off of a plant in flower to vegging after flowering. The leaves aren't going to look pristine and perfect through your whole grow until you're an expert grower.
Oh no! Don't pluck fan leaves unless they're mostly yellow and dying anyway. If they're still green they will help fuel your plant. It's like the difference between a 12-cyl engine and a 4-cyl engine. That's like saying the 4-cyl will move the same car faster because with less weight from the pistons will make the car lighter. It doesn't work that way. Keep all your fan leaves unless they're dying.
Also, what SICC is saying about topping is true. I'm trying it on the first available plant that meets the criteria which should be in a couple weeks. I'm going to try
Uncle Ben's technique. I can't wait. A lot of people on here have had good success with it.