I've been thinking about this for a fairly long time now....
In the first few episodes of SS, in the one when Shaina was having problems with Sunny, she asked Aryan, "Tumhaari beti ab hoti toh kitne sal ki hoti?" Aryan said, "Paanch"
Later, in the episode where the journalist murdered, before Aryan's breakdown episode, when he was talking to Ved, he said, "Do saal pehle jab Niharika aur Pallavi ki maut hui thi tab mujhe bhi laga th aki it's all over......"
Much later, when Deepika arrived, during the Cases Reopened Series, when Deepika saw Niharika and Pallavi's photograph, Aryan said, (pointing to Pallavi's photo)..... "Yeh do saal ki thi jab....."
Now even if there wasn't a huge time gap between the journalist's murder episode and the cases reopened episode, Pallavi was technically three years old when she was murdered, it seems Aryan himself, is confused about his daughter's age, definite loophole there, in the script.😆