The "tracks" on the leaf are leafminer, but that's not what caused the problem. Leafminer damage is unsightly, but other than that, rather inconsequential.
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Mites often cause the new buds to turn brown and be growth stunted. Look for that...
Do you feel like your fertilization could have been a little strong? If so, just water the next few times and see how they do. Over fert would be my guess, but it shouldn't be an issue. I'm guessing your plants still look nice and healthy.