Yeah, if you're doing 座禅 and you're feeling bad experiences, do seek counseling, and do cultivate your practice with people that know what they're doing. And corporations shouldn't really be involved in this, has has been said so many times. On the other hand, when I see stories like this one, well, comments must be made...
Farias looked at the research into unexpected side-effects. A 1992 study by David Shapiro, a professor at the University of California, Irvine, found that 63% of the group studied, who had varying degrees of experience in meditation and had each tried mindfulness, had suffered at least one negative effect from meditation retreats, while 7% reported profoundly adverse effects including panic, depression, pain and anxiety. Shapiro’s study was small-scale; several research papers, including a 2011 study by Duke University in North Carolina, have raised concerns at the lack of quality research on the impact of mindfulness, specifically the lack of controlled studies.
OF COURSE you won't have all unicorns and rainbows from practicing mindfulness, because one's own suffering is among the things which might come into one's awareness when one is cultivating awareness.
Also "guided" meditations aren't the same thing as what one generally encounters in Zen/Cha'n temples. It's never been clear to me how "guided" meditations are associated with mindfulness. It's telling though that no legit Zen person seems to have been quoted in the article.
The idea that mindfulness is harmful, "in general" is of course ridiculous. It's not a stretch to say that whole disciplines in the arts, athletics, and yes, even product design owe their existence to people practicing mindfulness.
Some people have suffered greatly, and this suffering can and does come up in practice. But that suffering often is also a catalyst for great compassion and wisdom; secular psychologists admit that.
But know what you're dealing with and what you're getting into. Stay away from hucksters, be they spiritual, corporate, or just plain hucksters.