Clawing is often a sign of N def which can happen a couple of ways.
Over feeding of Nitrogen in veg nutes or can also appear when not enough light is reaching lower leaves.
Sometimes,the low levels of light reaching the lower leaves means the N in the leaves can build up due to low levels of photosynthesis in these leaves.
In this case I would say it was a bit of N sensitivity when she was younger.
The clawed leaf also looks to have a little over watering damage from when she had a less developed root system again when she was younger.
In your PC box you'll probably want to start feeding bloom nutes now as opposed to after stretch due to height restrictions.
This will also help with any over nitrification/clawing due to the reduced levels of N in your bloom nutes.
Your PC grow is looking great and you'll probably want to start LST soon.
Keep sending those updates,this is such a nice grow to follow, even if I don't get to drop by as often as I'd like.
I look forward to your future tent grow as well.
Your doing a great job in a limited space, well done bro
peace
arty