did'nt Triveni and Shakti black-mailed Shagun a while ago based on Shagun's conversation with Sumer(before he died) when she was requesting Sumer to not to bring their son back from Alak?
Besides Triveni was the one who got the original Medical reports that said shagun's son was born perfectly healthy
So now why is Triveni so surprised to find out about Dev, Infact she even told Shagun that if she doesn listen to Triveni then she will kill her son Dev