Hi, I'm a first time pepper grower!

My pepper plants are at various stages of growth but nearly all of them are developing either one or multiple of these really strange leaves that are curved downwards, elongated in shape and hard to the touch.
I can't figure out what it is. This is most prevalent in my hydroponic Scorpion pepper plant where I pruned it but all the new leaves are coming out this way. The growth at the beginning was fine.

Could this be over fertilisation? Why would I have that in my other soil plants too though? The Bhut Jolokia developed two of those leaves too right after I transferred it into a bigger pot with new potting soil.

Image Links:

https://ibb.co/nnosHF

https://ibb.co/gLPXHF

https://ibb.co/ijqdra

https://ibb.co/gtZtPv

Please Help. Can't find the answer to this!
Thanks K