You’ve already got a pretty solid setup, so don’t worry seedlings are just a bit sensitive at this stage and small imbalances show quickly.
From what you describe (wilting + discoloration), a few things could be going on at the same time.
First, I would recommend increasing your humidity a bit. 65% is okay, but seedlings usually prefer it a bit higher, more in the range of 70–75%. Also, what is your exact temperature? 71°F (around 21–22°C) is on the lower end. Cannabis prefers it slightly warmer in the veg stage, ideally somewhere between 21°C and 25°C (70–77°F). They really like it warm and humid early on.
You should also make sure you have some gentle air circulation. A light airflow helps strengthen the plant, but be careful too much direct wind can actually dry out the leaves and cause that wilted look. If a fan is pointing directly at them, try reducing it.
Another important point: since you’re using living soil, it’s possible the plant isn’t getting enough available nutrients yet. The soil biology needs some time to break everything down and make nutrients accessible to the plant. In early seedling stages, this can sometimes lead to slight deficiencies or weak growth.
One thing that can really help here is a foliar feed. I often recommend something like BioTabs Boom Boom Spray. Apply it underneath the leaves as a foliar spray it works really well and stays fully within the living soil approach.
Overall, I don’t think you’re killing them it’s just a matter of dialing in temperature, humidity, airflow, and giving them a small boost while the soil biology catches up.🙏😊