well I don't know about that but I feel like Soni made it worse for herself... The discussion between P3G was about them not agreeing with Soni on giving extra food to Upen due to her brotherly relationship... they didn't once imply that Upen and Soni are acting beyond a brother sister relationship...Soni just made an issue out of nothing...
If anything, it was Diandra who created doubts in people's minds by what she said... Im glad Soni is out...
it could also be case of jiske maan mein chor hai, so she probably assumed somethg else alltogether