In my greenhouse, I raise both hydroponic and soil grown Big Beef tomatoes. The leaves have curled some but this happened last year too with no problems to the tomatoes themselves. They were great. This year I ordered new seeds from a very reputable major company and started about 30 plants. They are now about 18" tall and starting to put on fruit. The leaves are again curling some but what is really weird is that all along the leaf stems there are new starts coming on and lots of them. I always prune my plants when the starts come up on the main stem but I have never seen them on the leaves themselves. This is happening on all my Big Beef tomatoes both hydroponic and soil grown. I have one cherry tomato and it seems to be normal. Does anyone know what is going on?

There is something called "physiological leaf cupping" that causes tomato leaves to curl without affecting fruit quality. I found several articles from universites about it but this was the only one not a PDF:

https://agdev.anr.udel.edu/wee...

You might find the answer in there somewhere. Here is a quote:

"There are several possible causal factors for physiological leaf roll or cupping. Water relations are suspected in many cases where there has been a reduction in water uptake or increased water demand placed on the plant. The plant responds by rolling the leaves which reduces the surface area exposed to high radiation. High temperatures, excessive pruning, cultivation, and vine moving activities may also trigger leaf rolling. High nitrogen fertility programs followed by moisture stress may also trigger this type of leaf roll. Inadequate calcium moving to leaf margins may also cause a different type of leaf cupping. This is also related to interrupted water movement."

As far as your tomatoes' weird growth habits, I haven't a clue. But its interesting. If I where you, I would contact the seller and ask questions (send photos).

In my mind, it means that, for some reason, there is meristem tissue in the leafs rachis. That is entirely possible.