they often grow out of it.. so if the new growth looks fine, don't worry about it. Those early leaves are often fugly, so let it grow a bit and hope the new growth looks fine.
Mutations are more common than people realize. There's a reason why in the gardening hobby you typically plant more seeds than you need because shit does happen. You don't see that too often with marijuana, but the cost is a bit higher, i'd guess. I don't know the price of 'exotic' plants and such, but normal stuff is cheap, eh? When you plant 1-4 you may not notice as often, but over time it'll average out the same.
This isn't a gaurantee, but if it's environmentally caused it usually won't be "1" plant. If the soil was bad or the fertilizer was whacky out of balance or whatever, more than 1 would be impacted. e.g. i doubt your pH was wildly swinging at this early juncture, which can also cause the waviness in the leaves due to varying growth rates over time that results at different pH levels.
I don't abide mutants. I wouldn't trash it yet. I don't care of the first couple sets of leaves are fugly. Each to their own on assessing value of growing a defective genome. I plant extra so i can kill this stuff off without impacting my crop. Throwing out a few healthy plants to avoid unhealthy ones is worth it for me -- YMMV.