As far as Myanmar is concerned, some misunderstanding was created in the Indo-Myanmarese relations after 1962. This prompted Myanmar to allow Indian insurgents to use its territory.
Source : Institute of Defence Studies
But, according to other source, friendship between India and Myanmar grow up with treaty and a visit
India Myanmar relations finally got better after the two nations signed the Treaty of Friendship in 1951. Later, the foundation of their friendship became more robust and more meaningful after Rajiv Gandhi’s visit in 1987 (Source)
So, my question is when both nations signed a treaty of friendship and have conducted operations like operation sunshine to counter Insurgency, What event in 1962 is author referring to in his answer on defense studies which led to Myanmar giving land to separatist groups?