Whoa! I actually had pretty much the same experience about 11-ish years ago, in 2008. I completely forgot about that until seeing your comment here; wow, wow, wow!
A particular interest of mine is database systems (and by extension, distributed systems) and I’ve noticed this pattern a fair amount when reading database-related CS papers. It tends to feel like a small circle of researchers citing each other. Don’t get me wrong, that doesn’t say much about the actual quality of said papers, but it’s a pattern that I’ve definitely noticed. As a result of this, I tend to also make sure that I pay attention to seemingly interesting papers with low citations; sometimes, it immediately makes sense why they have low citations, while, other times, I find myself fascinated by the research despite the low citations.