As we all know now, Prerna has had the accident and lost her memory. She's gone 20 years back, where she's thinking she's still married to Anurag and Prem is still alive.
To me this is probably the biggest mistake ever by Ekta/Balaji.
Because 20 years back, Sneha was 7 years old and Prerna was still with Mr. Bajaj.
Prerna separated from Anurag around the time she was expecting Sneha, so if you add up the years, its a good 27-28 years since she split up from Anurag and Prem died.
According to the doctors Prerna's mind has now gone back 20 years ago and she has forgotten that she's married to Mr.Bajaj and has two daughters Sneha and Kasak. She still thinks that she's married to Anurag and Prem is alive.
If you take away 20 years, theres still 7 - 8 years left, where Prerna is still married to Mr.Bajaj and Sneha her daughter.
So I just think this is probably the biggest blunder made by Ekta/Balaji.