My SSG (Zola) offers an RSS generation option, so I turned it on. Several months later I realized it was broken for some reason and I hadn't noticed.
Nobody emailed me or anything (I'm not a popular blogger), so I just turned the RSS generation off
But it's so little hassle: just send the blog author an email saying vaguely what the problem is!
Someone emailed me about an issue with my RSS feed once. I don't remember what the issue was anymore, but I was grateful and I fixed it. Being the author of a tiny blog, it was just really nice to know that someone wanted to read what I wrote enough to care that my RSS feed was borked.
No blog is worth the hassle and honestly there is always a feed broken somewhere showing up in our reader we just wait for them to fix it. If they don't fix it then at some point it will just get deleted. That is just the reality of maintaining your own feed websites remove feeds sometimes and all you can do is go back see if its changed address and if not remove it.