I've had that happen a few times wen my plants were young the new growth came in pale almost like the nutrients werent getting to the new leaves fast enough. I've never had it last or hurt a plant but it wouldn't hurt to fertilize your plants, if you haven't already. I have seen this attributed to the use of a herbicide near by. Could that be the case? I knew that wasn't the issue with mine.
I have the same thing happening on a few of my plants right now. They are growing very fast and the new growth is paler, as if the plant is growing too fast to keep up. They are blooming and look fine otherwise. When it's happened before it always went away, I didn't notice it yesterday but it's obvious on several plants today.