This sounds like a slightly different issue … but you’re not wrong.
Cities that I had to import manually (by tracing its border by hand & collecting the data through bbbike) don’t have the blue boarder because that process didn’t provide me with that byproduct of data… It’s kind of a funky process that is covered in some detail in the GitHub repository of city data.
The OSM data is always improving, so the cities that I couldn’t import in the past might be usable now. I’ve got this thread open for suggestions on new cities to add … I, admittedly, need to actually work on this - but it’s the best place for these requests right now.