Why does the borders of boundaries actually of India keep changing
Answers
Because, that is the reality. What each country calls as their map is a figment of imagination. A lot of major countries claim lands that they don't control. China claims Arunachal Pradesh and Pakistan claims the whole of Kashmir (except areas controlled or claimed by China). India claims both.
The question really is what parts of those regions these countries control. Can China control Arunachal Pradesh? No. Can India control Aksai Chin? No. Can Pakistan control Indian part of Jammu & Kashmir? No. When these three countries have nuclear weapons, is there any reasonable way to change borders from here on? No.
Then why do these countries show it in their map? To please the hardcore nationalists at their home.
Indian leaders however are already clearer in accepting the current map as the reality. The problem is that China and Pakistan are not arguably accepting the reality now. From what I have read, Indian leaders would be open to giving up its claim for Pakistan's Kashmir in return for Pakistan giving up its claim of India's J&K. In the same way, Indian leaders would be open to India giving up Aksai Chin while having China give up claim over Arunachal.
This is why India doesn't protest much about maps without PoK and Aksai Chin. As long as the maps show Arunachal and Jammu Kashmir firmly as parts of India, that is one India desires. Because, that is the reality. The rest is mere fiction.