I'm a first-year PhD student working alongside my supervisor on my second paper. So far, the process has been that I write a draft, he adds some comments/text where necessary, and we re-iterate. This is mostly fine, but I have noticed a pattern with his revisions: he self-cites a lot. These references are all somewhat relevant in context, but usually plain redundant. As an example, he might change "(Author et al. 2021)" to "(Author et al. 2021; Supervisor et al. 2022a,b, 2023)". In my first paper, my supervisor was listed as an author in over a third of the cited references. Out of those, I only added two.
I have some concerns about how this affects readability, but my biggest gripe is that it just looks bad. Maybe I'm overly dramatic, but I don't like how the paper I wrote to 95% is so plainly used as a way to increase his citation metrics. To the reader, it may come across as me parroting his research, which isn't the case. I have a good relationship with my supervisor, but I don't know how to bring this up in a non-accusatory way. Is this a problem I should be concerned with and, if so, what can I do?