Not sure what issues you ran into, but this isn't necessarily a bad thing. I had a similar experience with Elixir, where some libraries had been last touched two years ago, but did the job with no issues whatsoever.
The desire for libraries that are constantly in flux stems from the “move fast and break things” mentality, mixed with the continuous flow of breakage in mutable languages. If you move slow and do things well, you can often build some reliable with a fraction of the effort.
I have the feeling I encounter a lot of these situations when I look at libraries I would need for a project. It's rather uncommon I see a very active project in Ocaml (even if there are some indeed).