Is this one of the reasons?

In yet another blow to the ruling BJP, the Shankaracharya of Puri, Swami Nischalananda Saraswathi  said that under Narendra Modi, work that had remained stuck for 500 years was completed but the greed of the BJP resulted in some major losses. 

“What happened in Ayodhya?… So, I had commented back then, too…. Shri Ram ji walked from Ayodhya towards Chitrakoot… from Chitrakoot to Nashik, aur sab jagah BJP haar gayi (and the BJP lost everywhere),” said the Shankaracharya.

Last week, Swami Avimukteshwaranand Saraswati, the Shankaracharya of the Jyotir Mutt, said in an interview that the ‘pran pratishtha (consecration)’ of the Ram temple in Ayodhya was hurriedly done, due to elections, and his order considers it a political event.

Even at the time of the consecration ceremony of Lord Ram in Ayodhya, the Shankaracharya said he would not be attending the ceremony as it was not proper to perform the consecration, according to the scriptures until the construction of the temple was complete. 

Responding to this, then Union Minister Narayan Rane questioned the contribution of the Shankaracharyas themselves to Hinduism.

Sources in the RSS believe that this castigation of the Shankaracharyas by Union Minister Rane was one of the reasons why the Sangh was upset with the BJP. 

The Shankaracharyas are considered the "supreme authority" in Hinduism and for interpreting Hindu scriptures.The heads of four mutts are highly respected for their knowledge of the Vedas and their ability to interpret them. 

Shankaracharyas are also known for their contributions to the development of Advaita Vedanta, a school of Hindu philosophy that emphasises non-duality and the unity of all reality.

Criticizing such revered figures deeply hurt the sentiments of the Sangh and its followers and no attempt was made to assuage their feelings.