With 5weeks in it's most likely your plants metabolism at work. It's redirecting all it's energy toward bud production so the leaves aren't producing chlorophil anymore. Instead all the sugars they are making are going to the buds. Do you know how long your strain is supposed to be flowered for?
this is just some bagseed bud. thanks for the info. even though i dont understand wants going on with my plants..... i get that its normal thanks Godsend +rep
You didn't mention what those two colors are, but I suspect that some are green and others are turning yellow. Not to worry, at five weeks, that's normal. You will be getting more yellow leaves as the flowering cycle progresses.