NEW DELHI: Shiv Sena ’s decision to abstain from voting on CAB in Rajya Sabha marked a change from the stance it adopted in Lok Sabha two days ago, but fell short of Congress’s expectation that it vote against the contentious bill.Congress had conveyed to the Sena leadership its displeasure about the party’s vote in favour of CAB in the lower House on Monday, saying it was against the understanding in the Common Minimum Programme for the Maharashtra alliance that on issues where they had a disagreement, the Aghadi partners would consult each other to hammer out a common stand.Sources in Congress said a strong protest was lodged with Maharashtra CM Uddhav Thackeray who blamed the vote on the citizenship legislation in LS on “confusion” among MPs. But while Thackeray’s statement on Tuesday pointed to a re-think, it fell short of Congress’s satisfaction.Again, on Wednesday, Sena’s vote in RS left the Congress-led opposition disappointed. Congress left no ambiguity about its anger with Sena. Rahul Gandhi tweeted, “CAB is an attack on the Indian Constitution. Anyone who supports it is attacking and attempting to destroy the foundation of our nation.”The Maharashtra outfit recently broke its decades-old “Hindutva” alliance with BJP and formed a government in Mumbai with Congress and NCP, effectively moving to the opposition camp.Sources said after the debate in LS, a senior Congress leader took up the issue with Thackeray, arguing that divergence of view on a serious issue like CAB was unacceptable. It was said such dissonance would hurt the durability of the alliance.As the debate on CAB pointed to the first instance of ideological contradiction in the Maha Vikas Aghadi, there were questions among partners if the alliance would be durable enough to last its term. There was, in any case, a concern that the alliance could become a victim of its internal contradictions. Sena’s vote for CAB in LS and its decision not to reverse itself fully on the floor of Rajya Sabha appear to have aggravated the worry.With the CAB exposing the fault-lines within the Aghadi, the fear is that BJP would play on it at every possible occasion to drive a wedge among the partners.The Congress plaint was the reason why Thackeray made a statement on the eve of debate in RS, complaining that Sena’s grievances on the bill had not been addressed. It led to a flurry of comments from Sena leaders suggesting a possible change of heart.Sources said even Congress president Sonia Gandhi had sent a party MP to the Sena benches to ask them about their final decision on voting and had appeared miffed at the response. The 18-member Sena would not only have made the opposition score appear less dismal, it would have given it a symbolic victory over the ruling BJP alliance and even provided a justification for the decision to join hands with the Hindutva outfit: a move which was mocked by Union home minister Amit Shah in Lok Sabha on Monday to take a dig at Congress’s “secularism” plank.