That means an inconsistency has been detected before. Which obviously isn’t what it says, I’ve just been too lazy to fix it until now: lib/db: Improve error message on meta inconsistency by imsodin · Pull Request #6751 · syncthing/syncthing · GitHub
The profile shows that it’s checking globals, spending all it’s time in the db layer. Maybe there’s something wrong with your db storage, but maybe it’s just that slow. As it’s not maxing out cpu (one core), I’d actually expect IO wait time being a culprit.
More technically: What is taking up the time is looking up all the entries in all global version lists individually. That could probably be sped up a lot by using one iterator per device instead of doing lots of Get calls. However that would make the code much more complicated, when instead using Audrius words: