mine was doing the exact same thing last week! there starting to recover now. I added the cal mag I finally got along with a little Epsom salt and it seem to be what help it. I'm still not sure what it was but looked just like that. on this plant symptom chart it looked like a cal mag def but still till now im not sure because I tried several different thing from lighting to thinking maybe even root rot with mine. Hope you find the answer tho! that be cool for next time we see this, It really affected my growth :/
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