Pulling the leaf will inspire the plant to grow more leaves (a good thing).
I really think aphid damage. Their damage persists long after the infestation is gone.
Just might want to make sure you check them daily for a bit, if you don't, and don't use harsh chemicals, eventually a lady bug army will move in, and destroy the aphid population. But you will have a lot more damage in the mean time... better to keep them picked, and let the lady bugs clean up what you miss.
If I remember how aphids work properly, the yellow spots (which can also be indicative of nutrient deficiency, or some of the virus's peppers are prone to) are there because the aphids suck the nutrients out.
With under fertilization, it is usually not the new growth, rather usually the old growth, and the plant sort of cannibalizes the old stuff to help the new.
The viruses slow/stop the circulation of nutrients through the leaves, causing yellow mottling.
Over watering can cause the entire plant to turn yellow, because while it needs nutrients, its full of water and can't take in what it needs to grow. PLUS over watering can lower the amount of nutes available to the plant in the soil (had this happen to me, after TS debbie hit, and dumped three feet of rain on my garden over a weekend, any nutrients in the topsoil were washed away. had to wait until they were dried out a bit, and foliar feed, in conjunction with replacing nutes in the soil...).
Any way, its not a huge deal, you don't even really /have/ to pull the leaf. Your plant is still in grow mode, and will be producing a lot of leaves any way.