What made Zeenat turn NEGATIVE AGAIN?

Til couple of weeks back (not very long ago) Zeenat had started liking Zara and supporting her marriage with Kabir as well as her sister Ruksar! My question is what made her go negative again and start to plot against Zara again with Shahbaz before her and Kashan snatched the whole property and house away from Shahbaz! I mean, Kashaan I understand he loves Zeenat and is controlled by her- she successful manages to manipulate him all the time as she is very manipulative- but what made Zeenat go against Zara again? Was it Zara's decision to live in the outhouse and live a simple life? Or was it her urging Kabir to work and start earning? After all Zeenat purani soch ki aurat hai and tab shyad Zara uski Nazar mein ghir gayi

I think zeenat believes that ruksar is in this state is because Kabeer wanted to divorce ruksar because he loves Zara and zara cannot share him with anyone. So is he believes that Zara is the main reason that ruksar is hurt.
Also after ruksar became a child, she favors Zara over Zeenat, which made zeenat jealous since ruksar is zeenat's sister but didn't say much at first because Zara was helping ruksar ( givingwr her a bedroom, buying chocolates ). But then Zara took ruksar to the outhouse to get Kabeer there and zeenat is worried about ruksar's health. So she didn't like that fact that ruksar was being used by Zara to bring Kabeer closer to her and the fact that ruksar would listen to Zara over zeenat, just made zeenat angry...

for me Zeenat is what we call here in south america "bareface" she aligns herself as needs be as long as it benefits her, now she has finally got Kashan to do what she wants cos she has always felt that as the elder daughter in law she was not given "her due respect" this is her way of putting Zara and Kabir "in their place" cos they were the favoured ones!!