In the latest dance bts, Shravani is dancing behind Shivangi. And I don't think she has been made Naagrani as yet.
Don't tell me they are gonna show Maha Naagrani acting as Naagrani. Or something like if Maha Naagrani is in charge, only she will be the acting Naagrani and will hold the highest command or something.
Firstly, from Sumi's description Shivangi was only supposed to protect Naagmani in original Naagrani's absence. Considering that Bela is back she should be crowned again as the rightful queen and shouldn't be made to look like she is subservient to Maha Naagrani or anything like that.
I guess because Mouni was coming back for a cameo appearance and her character in the previous seasons was also from Shesh Naag vansh and Bela is the Naagrani of Shesh Naag vansh, they probably didn't want to show Mouni's character addressing Bela as Naagrani considering the 'seniority'. But then again they could have shown Shivangi and Bela as friends too.