m0useanswered grow question 5 months ago Could have been something spilled on the leaves and some light burning from it, Could be the start or something else.
Confirm your feeds are supplying all the recommended nutrients and if it is, this is likely just a one off, If it is progressing then its something you need to look deeper into.
As your growing in soil and with RQS amendment pucks it will be harder to tell. If hey have not been amended they may need more soon. Normally its done every 3-4 weeks as a top dress with amendments. and if its getting runoff that will be leaching the soil a bit.
hears a leaf chart that's pretty informative.
https://420life.com/wp-content/uploads/2021/10/Marijuana-Leaf-Deficiency-Chart-scaled.jpg
Good Luck!