Sorry no response as yet.

How are your plants doing? Did the condition get worse or did it clear?

I did some research as it seems many people were having the same problem about the same time. I think the plants were getting overcrowded already in their pots. After transplanting to the 4" pots they just exploded in size, but its still too soon to put them in the ground. I posted some pictures at the link below.

In short, the problem hasn't gotten better but it hasn't gotten worse. I started hardening off a few days ago, and that seems to have reinvigorated the seedlings. So I think we'll make it to last-frost just fine.

Here is a link that might be useful: Seedlings explosive growth after transplanting