I’m on 8.5.3 and this is still an issue.
At the moment, I’m alternating between projects using a seconds and minutes ruler, and those needing a beats and bars grid, and the fact that this isn’t saved per project is really annoying. Having to reset it each time you open a project is one of many small issues that slow everything down - since I upgraded from Cubase 5 last year, I’m spending about half an hour a day extra because of all these new problems, which all adds up. Really pining for the stripped down speed of Cubase 5 rather than the overblown sluggishness of 8.5…