Happens often and most of the times is it because of a misunderstanding. Usually we actually agree with each other but we think we are disagreeing and arguing about how the thing we agree on is correct. I have seen this happen with two coworker many times and it makes me laugh every time until it gets too serious. I actually had this kind of “discussion” yesterday, my coworker said he couldn’t see change x in my PR and I told him how it was before and how it is after the change and then it became heated (I assume it is because he wrote the code and the tests) he stepped back when I told him even the tests expected the faulty state then he understood what outcome we needed and saw that the change was there and it was actually correct.