There are numerous proofs to claim Lipulekh-Limpiyadhura-Kalapani belongs to Nepal that Nepal possesses. Few of which have been mentioned below.

Article 5 of Sugauli Treaty clearly states that Lipulekh, Kalapani, and Limpiyadhura belong to Nepal. But India has been trying to create a dispute regarding the point of origin of Mahakali river. Not only that India even further manipulates the fact of Point of origin of Mahakali river by claiming small stream of Lipulekh as the point of origin of Mahakali River.
Survey of India had released a Map called “Gadhwal Map” in 1827 A.D. which also clearly shows that Limpiyadhura is the origin of Mahakali river. Hence there is no confusion regarding the point of origin of Mahakali river.
Survey of India had also released a map called "Nepal & Countries adjoining to the south, west & east compiled in the office of Survey General of India" which also clearly shows that Limpiyadhura is the origin of Mahakali river again there is no confusion regarding the point of origin of Mahakali river.
In the article 3 of the Treaty mentioned by the then Junga Bahadur Rana , Prime minister of Nepal has clearly mentioned in his own Hand written Document that Limpiyadhura is the Origin of Mahakali river. This document is well preserved even at today’s times. Again there is no confusion regarding the point of origin of Mahakali river.
Also, Google map and other scientific methodologies also proves that Limpiyadhura is the point of Origin of Mahakali river.
A Census was held by Nepal on 1961 A.D. in Nabi, Kuti, Kalapani, Lipulekh, Limpiyadhura & people residing at Nabi, Kuti, Kalapani, Lipulekh, Limpiyadhura all participated actively in the Census and also participated actively in the election by polling their votes in 1960s.
There is Land revenue tax bills paid by the people residing at Nabi, Kuti, Kalapani, Lipulekh, Limpiyadhura to the Govt. of Nepal.
There is other 120 other legal documents like official letters exchanged between the then Government of Nepal and East India Company and many more which clearly proves that Lipulekh, Kalapani, and Limpiyadhura belong to Nepal.
Therefore, there is no any dispute or problem regarding the Sugauli Treaty nor regarding the true ownership of the regions like Lipulekh, Kalapani, and Limpiyadhura. These lands were/are the sovereign regions of Nepal. India has encroached Nepalese territories in a complete daylight.