Writing feedback and being overcorrected

So I just had a private tutoring session on another platform and I sent my tutor a copy of my research proposal to be receive feedback. I had used this same proposal when I was applying to enter my Masters program and had it checked by numerous native speakers (most of whom work in academia). However, I made some updates to my proposal so I wanted to get it checked again to make sure it still sounded natural.

After sending the file to my tutor, he proceeded to rip apart every single sentence, claiming that they were hard to understand or that the vocabulary used sounded unnatural. If this was my first draft, I would just take the criticism, but multiple other native speakers had already checked most of it and said it was fine.

I know it sounds a little strange, but I was actually quite upset after the lesson because I don’t know if all of the people who checked my proposal before didn’t do a thorough job or if my tutor was just trying to find problems with my paper to seem knowledgeable.

I know that everyone has their own writing style which might have played a role in this, but has anyone else had this experience?