I had been to Hajj and as a Musafir, I was offering Qasar.
But later on, during the Hajj days, I got confused because of a few people who were overthinking. I asked my mother to pray in full (I was reading in Jamaat). She prayed one or two salah as full and later, we again checked and continued Qasar. I had clarified with many mufti's and they said it is fine as you were confused.
My questions are as follows:
1.Will any mistakes in salah cause an issue in Hajj?
2. I accepted my mistake before my mother and also Allah SWT and repented, but still, I get thoughts like I did a big mistake.
I had checked all my mistakes with mufti's but they replied with ‘it’s okay, there’s nothing to worry about’. But I get worried now and then.
بِسْمِ اللهِ الرَّحْمنِ الرَّحِيْم
In the name of Allah, the Most Gracious, the Most Merciful
Any mistake made in regards to the number of rakaat, due to a person being a Muqeem or a Musafir during Hajj, will not cause issues with one’s Hajj
Given that you clarified your Muqeem/Musafir status with multiple Muftis and sought forgiveness for any shortcomings, you have done your best to fix any mistakes. Please remain positive and hopeful of the mercy of Allah.
Allah (exalted be He) says in the Quran: Indeed, Allah does not forgive association with Him, but He forgives what is less than that for whom He wills. And he who associates others with Allah has certainly fabricated a tremendous sin.
Only Allah knows best
Written by Maulana Muddasser Dhedhy
Check and approved by Mufti Mohammed Tosir Miah
Darul Ifta Birmingham
 An-Nisa verse 48