It's time to bring this up now it seems.
The way to approach this here may seem obscure and fringe to the extreme, but hear me out. I'll enter this by talking about the very commonly used gyan mudra.

This hand position is probably the most widely spread, whenever someone teaches yoga they will tell you to sit in lotus position and place your hands on your thighs in this position. This is very harmful.
Wait what...?
This position creates a mental focus. As Sadhguru teaches here, it's enough to just sit and observe your breathing and your focus will land on your 3rd eye chakra.
https://youtube.com/watch?v=a0jJi6OI_4o [Embed]

All good so far. But what also happens is that it forms the "promiscuity" mindwave. This is something we found when practicing with djinn and aliens over telepathy and channelling. They pretty much confirmed, yes; if you use gyan mudra you will have a harmful mindset if you are a normal mortal human.

So why can this be spread widely? Why is one of the most influential gurus of India teaching something harmful?
Simple as this: we are in the Kali yuga, the endtimes. Humans are rotten to the core and mostly everyone already has the "promiscuity" mindwave. This is a sure way to hell and an afterlife of torment. Teaching the mudra widely will not make it worse. Rather, there is a small chance that someone will learn it and use it correctly.
In past ages this mudra could not be taught to the general population, but only to dedicated yogis and monks in temples or the deep woods/mountains.