Overall your plants look fine to me, don't worry.
What power is your lamp set to? If it is set to more than 80% I would raise it to at least 50cm.
Your plants are still young and this might be what is stressing them.
Raising the lamp could cause then to stretch up a bit more, and this is what you want isnt it?
Such wavy and thick, slightly leathery leaves can be an early sign of over watering.
If your pots don't feel slightly light - or noticeably lighter compared to just watered -
try and wait a half a day or a whole day longer before you water them again.