I had this one teacher in university (not yet a PhD but was working on it) that I ended up taking like 4 different classes from in university. Although he was brilliant and experienced having worked in the industry for 30 years or so, and was naturally a very good teacher and very passionate about what he taught, it's a simple fact was he was new, but he was very humble and transparent about that. The first course I took from him was only his second time teaching that course (or any course), and the other three were each his first. All these courses he built the curriculum himself. Again, he's an excellent teacher, one of the best I ever had, but he was still working out the kinks in his tests. He was being very transparent with us students about his process of choosing to award partial or full credit for questions and problems he decided weren't fair, or were worded ambiguously, always taking feedback during class after getting our graded tests back.

I had a few other courses like that too, and I feel like that system (decreasing the weight of problems that aren't fair to students) is generally a better system than simply grading on a curve. The former is more granular, differentiating poor grades due to lack of study from poor grades to a faulty test. It also provides a clear direction for improving the curriculum next semester. Grading on a curve often feels like a copout to avoid the labor involved in improving the curriculum. BUT on the other hand, if the class really went so poorly that nobody understood the material or if the test was almost totally unfair, then imo grading on a curve could be the fairest solution for the students. There's no perfect solution there, the students time is already wasted, better to give them the benefit of the doubt in that case.