To be honest, the caller raised a valid point but she was unable to express herself clearly. And by saying I'm sorry if...at the end. Well that just ruined it.
Diandra's expressions were quite telling. Her eyes said a lot. Although I haven't liked Diandra much, I get the feeling that she is a very observant woman and picks up on things quickly.
As for others such as Praneet, I think somewhere deep down they have noticed things but are choosing to sideline it on purpose. Hey if viewers have sensed it, I'm sure ghar wale bhi dekh rahe hain!
She got under pressure and in the end kinda ruined it but still kudos to her for bringing it.
Diandra should express it some more.
Others must have noticed it too but as you said, chose not to say anything as it can create a big issue and they also don't know how its portrayed outside so they stayed out of it.