I have only seen it on two leaves so far but have noticed the little leaves around my buds are kind of curling down ward. Rest of the plants look good leaves are sticking out good.
Always try to upload a clear picture of any issues you may have to allow the community to assist you.
Add anything else you feel would help us give you a most informed answer should be included. Feel free to elaborate, but short and to the point questions and facts will help us help you in a more efficient manner
Thanks!
Please include a decent picture of the plant overall in natural light (white) and be as detailed as possible. Age of plant, what method of measuring PH and TDS etc.