What specifically are your questions?
Your plant's brown leaf necrosis on lower growing fan leaves is due to an overly wet media. Most likely watering too frequently. This is very easy to do when a plant is young and doesn't have much of a root structure. Cannabis needs to go through wet and then dry cycles to grow correctly. Try using an inexpensive moisture meter to determine when to water. New growth suggests you've worked your way through the watering issue.
It looks like your media has pulled away from the fabric pot in some areas. Fill that gap in with fresh soil. The air gap makes thoroughly wetting the media almost impossible. You want to thoroughly saturate your plants on each watering. Allow the time for the soil to dry back before watering again. Depending on pot size, this could be as long as 4-5 days and possibly longer in some situations.
The last thing I noticed is your temperature and humidity are both too low to support robust plant growth. During veg, your VPD target should be about 1.0kPa. Your daytime temp during veg should be around 78F under LEDs. References to cooler temps which you received by the previous poster are for HID lighting. LEDs require slightly higher temps.