Tough to say my guess it’s a combination of that soil and your watering habits - if you can get so peat at a local hardware or gardening center or farm store - add some perlite and lime and you might be better off ? If your not in hurry then ride it out she may pull thru and thrive later when she can use the nutes
This is what is written on their website, high-quality acidic growing soil specially mixed by Toff Marom Golan for Hydro-Shop, exclusively, according to exact specifications that meet all the plant's requirements.
Soil based on peat, perlite and coconut fiber in the appropriate doses and enriched with vermiculite.
Extremely dark soil, with excellent drainage to prevent water lines for ideal development of the root system.
I had problems at the beginning of watering and also the lighting was for a few days really close to the plant until I realized I was making a mistake