system
Given the following post, respond as if you're commenting on Reddit:
human
Witnessing unequal grading by professor as a TA

I am TA for a new course at my institution and am responsible for tutorials, office hours and grading. There are 3 TA for the class and we have all noticed that grades in our Google spreadsheet for marking have been changed by the professor. The average of the class is 85-90% but specific students harass us over their grades and the professor gives in and gives them 100% on labs and midterms. We mark according to the professor's marking notes but when students argue the professor makes exception for some students and incorrect/missing information in answers gets marks anyway. For example the marking key says that they need to write the scientific law used in their answer but they leave it out. Other student loses marks but student that complains gets full marks. Sometimes the teacher says to mark based on what we feel about the answer and doesn't give marking key. 

One TA talked to the professor about this but the professor told him that it wasn't important and they were only grades. We think this is not fair to student who accepts grade and doesn't ask for change. Some students go from 80% to 100% from complaining and have straight 100%s. Is this against school rule and ethics? If so, who would we talk to about it as a TA?
gpt
I get that this is frustrating to watch, and it's not how many of us would handle student complaints, but responsibility and authority over grades ultimately lies with the professor. If you've talked to the professor and they don't care, there isn't really anything you can do. 

(Well, unless you're in the UK or another country where there is an "external examiner" for every course. IIRC they usually focus on exams but at some universities they review all aspects of the course. However, tattling to them would be a fairly extreme step and likely torch your relationship with this professor).