The Chinese backstabbing story seems more farfetched the more I dig into it. A lot of it might just have been Nehru's misreading from his self-indentified perch as an "elder statesman" and "bhai bhai" thing was a delusion manufactured in his head. In his defense, it seems that other PMs like Modi don't seem immune to a special feeling towards the Chinese. Both Doklam and the recent skirmishes at Pagong lake have proved that in Modi's case.
Condescension was also a specialty of Nehru given his upbringing and that might have played a role. Nehru condescended to those he did not considered polished enough - be they Indian or Chinese. In Gentlemen Spymaster,
RN Kao's quotes an interesting incident which lends credence to this:
"‘This was my first presence at an international meet and I was impressed with the solemnity of the occasion and the gravity which seemed to hang in the air. At that time, China had not widely been accepted as a respectable member of the international comity of nations, and as we (India) were one of the few countries that had established diplomatic relations with China, Prime Minister Nehru had taken upon himself the responsibility of introducing Zhou Enlai on the world scene. Or, at least, so he thought. In later years, I learned that Zhou Enlai had mentioned to some reporter that he had not met anyone as arrogant as Jawaharlal Nehru and in support of his statement, he had said that it was incredibly presumptuous on the part of the Prime Minister of India to have introduced the Prime Minister of China on the world scene. Well, whatever Zhou’s ego might have been, the fact of the matter is Nehru did help China to gain recognition in the international field. In fact, in that process, we (India) earned a lot of odium,’ Kao observed."