Research into mindfulness emphasises the benefits, but tends to minimise the harm. Some research fails to mention any risk at all. This makes it hard to devise a mindfulness program that doesn't cause harm.
Mindfulness in schools is applied to the entire school population.
Mindfulness in schools is usually delivered by teachers, and not trained therapists or psychologists.
The combination of taking the entire population, including children at higher risk of harm, and not understanding how that harm can be caused, and using people with minimal training to provide the programme, means that some people get harmed.
https://journals.sagepub.com/doi/full/10.1177/01410768166441...
https://www.brown.edu/research/labs/britton/sites/britton-la...
https://www.sciencedirect.com/science/article/pii/S027273581...
> Mindfulness just means being aware and non-reactive
Mary is a 10 year old girl. She is raped once a week by her step-father. You can see how being "aware" and "non-reactive" might cause extra harm.