One possible explanation

I think what messed up SRGMP is a combination of

Gaj's greed to rake in more moolah by allowing people to vote multiple times.

and

Shaan, mentors and contestants alike promoting regionalism. Voters get easily sold on these sensitive issues.

If the news of Nihira and Hema ending up low on the votes is true especially after their flawless performance on the SLB show, I am thinking that may be:

The sincere voters (who vote based on merit) probably vote only once and must have voted for the best singing. But the supporters of singers like Rajiv (just an example) must have panicked after his performance, and must have voted numerous times just to keep him alive. In this madness of trying to save their favourites, the true singer might have ended up with lesser votes than the rest !!!

Just a thought...

Well, the janta doesn't necessarily vote on best sur or best taal, they just vote on whoever they feel like voting for. All the reality shows are fully aware of this. You can't expect everyone in India to be well versed in music. It is a given that the janta will vote for who they like regardless of singing merit. Say for example, there was a Miss Universe competition going on, and they left it to the entire world to vote on whoever they thought should win. Even if the girl from India was the weakest contestant, honestly, who would YOU vote for? 😉

I feel this is a classic case of human psyche.

Mentors and their mentometers proclaim Nihira as the future of India.
Nihira's supporters are quite confident that she will get the highest votes. They will still send in their votes but see no need to vote multiple times. There is really no incentive for them to vote so desperately.
The supporters (whether based on region or looks) of singers who are not rated high by the mentors sense trouble, and in order to save them they send in votes in huge numbers. The sense of desperation is high in this case.
This voting pattern could ideally push a good singer down and bring a bad singer (with lots of support / sympathy) up in the ratings.
Sounds plausible ???