This is not the case for me. I just now searched in mobile Chrome for "Lakeview Chicago" and the mini-map static image has a purple outline around the neighborhood. Clicking on that took me to Google maps with the neighborhood outlined in a red dotted line (which is harder to see, but obscures less of the other features/labels on the map). This was on Android, in the maps app, just now, but I've seen the same thing in a desktop browser.
Ah, you're right. It looks like the issue I'm complaining about only happens for "line" features - e.g. a river, or a road (https://www.google.com/search?q=route+66).