Sadhguru:
During Mahasamadhi entire energy body is projected out, and during AP, only one portion of Pranamayakosha is projected out. People will usually get scared by feeling/being lose in the body (Vyana Vayu) and label that by Mahasamadhi in their mind, due to their mind being filled by various assumptions, including the ones I'm presenting.
Sadhguru's wife Viji allegedly preformed Mahasamadhi using Shambho mantra (most gentle form of Shiva) and exited the body through hearth chakra (burn mark was visible on the body) by sheer intensity of emotion (merging with object of devotion) which found little awareness. What is interesting, Sadhguru said she didn't completely dissolve immediately upon leaving the body, so he was still expecting her to help him with consecration, but she was approached by a different master who helped her dissolve completely.
Sadhguru:
That being said, Sadhguru will always give a copper ring to people for their left ring finger, when they do intense Sadhana (to not go beyond Nirvikalpa Samadhi). He rarely explains how even Sadhana works in details, and he never explained the rings. While all meditators where doing Shoonya meditation (nothingness) Viji felt that the ring was stopping her, so she removed it. After the incident, Sadhguru had to explain the purpose of the ring.