You're diary says peat and perlite mix. But your plant looks like the soil is over fertilized. Was it a prefertilized mix you started with? If not, peat can be very acidic. Maybe its thrown off the ph? I still think burning though cause its been going on since week 1. Id check ph and ec as another said.
Just my thoughts,
Best of luck! Happy Growing!
they both dont look healthy. The other just healthier........At this early stage having burnt leaves is due to wrong ph and therefor nutrient block or way too much nutrients. Check ph of water/nutrition. If that is fine, you must change EC