You want to use the word "invalidate" in place of "break"? OK, whatever.
But you do know that Sikhs commonly speak of "ਉਹਨੇ ਅੰਮ੍ਰਿਤ ਤੋੜ ਲਿਆ" in Punjabi. ਤੋੜ = break. By committing a bajjer kurehit, you break your Amrit. (Or invalidate it, if you prefer.)
A person who turns his back to Guru ji becomes a bemukh:
ਸਤਿਗੁਰ ਤੇ ਜੋ ਮੁਹ ਫੇਰੇ ਤੇ ਵੇਮੁਖ ਬੁਰੇ ਦਿਸੰਨਿ ॥
Those who turn their faces away from the True Guru, are seen to be unfaithful and evil.
ਅਨਦਿਨੁ ਬਧੇ ਮਾਰੀਅਨਿ ਫਿਰਿ ਵੇਲਾ ਨਾ ਲਹੰਨਿ ॥੧॥
They shall be bound and beaten night and day; they shall not have this opportunity again. ||1||
ਗਉੜੀ (ਮਃ ੩) ਅਸਟ. (੯) ੧:੨ - ਗੁਰੂ ਗ੍ਰੰਥ ਸਾਹਿਬ : ਅੰਗ ੨੩੩ ਪੰ. ੧੨
Raag Gauri Bairaagan Guru Amar Das
Surely you would agree that a person who has turned his back to Guru Sahib, commits bajjer kurehits, is a bemukh, and is beaten night and day has broken their Amrit, no? You would say that a bemukh is still an Amritdhari?
I think the reason he is asking why people break their Amrit is because he is concerned he might break his, that is, he is asking about ways to stay strong in his Sikhi.
1. First of all, a question for you: Are you a amritdhari Sikh, believing Sikh, patit Sikh, or a non-Sikh? If so, Christian, Hindu, or Muslim?
2. Second, here's your answer:
ਅਚਿੰਤ ਕੰਮ ਕਰਹਿ ਪ੍ਰਭ ਤਿਨ ਕੇ ਜਿਨ ਹਰਿ ਕਾ ਨਾਮੁ ਪਿਆਰਾ ॥
God automatically does the work of those who love the Name of the Lord.
ਗੁਰ ਪਰਸਾਦਿ ਸਦਾ ਮਨਿ ਵਸਿਆ ਸਭਿ ਕਾਜ ਸਵਾਰਣਹਾਰਾ ॥
By Guru's Grace, he ever dwells in their minds, and He resolves all their affairs.
ਸੋਰਠਿ (ਮਃ ੩) ਅਸਟ. (੧) ੫:੨ - ਗੁਰੂ ਗ੍ਰੰਥ ਸਾਹਿਬ : ਅੰਗ ੬੩੮ ਪੰ. ੨
Raag Sorath Guru Amar Das