Your conclusion on the situation is very much dependent on the meaning of buffer and what actions are agreed within these buffer zones between fingers 3 to 8.
As a preamble the following is my understanding of the situation in Pangong Tso.
1)Finger 2 is the Chinese interpretation of the point of LAC whereas the Indians consider it to be finger 8. The Indian position is based on the furthest point where China has a historical structure.
2)In recent history, finger 4 is the point of demarcation. This is a result of China agreeing to dismantle a permanent structure build between 2014-2015.
3)Consequently India had active control up to finger 4 with patrols ending at finger 8. Conversely, the Chinese would actively patrol up to finger 4 with occasional patrols to finger 2.
4)The most recent clash was at finger 5 and the eye to eye was at finger 2.
5)If the agreement was that India's side of the buffer is fingers 3 to 5 and the Chinese side is from fingers 5 to 8, then both sides have conceded by way of buffer zones.
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Indeed it is dependent on how both sides are defining their borders but it is my understanding that China's claim or interpretation of there the border is is at finger 4. Not finger 2. If it is the case that China's claim is to finger 2 rather than 4, while India's is at finger 8 which is no disputed, then China has at this moment lost fingers 2 to 4. China used to patrol up to finger 2 on some occasions while Indians patrolled up to finger 8. If this also happens to be where each side claims their borders go up to, then the position of the current buffer zone is a good compromise somewhere in between, maybe with slight favour given to China.