BC version 3.1.2. As the title says! Its the same in both 2D and 3D views. Tried reinstallation of software etc. Pic below. Every single road is broken into random sized sections?!!
I think this is actually a response to a waypoint named Mother Dunch's Buttocks. It's a very specialized filter. OK maybe not. What is the name of the basemap you are using? Since there are different ones in different regions, I want to make sure we are looking at the same one.
This isn't something I've seen in the map products I've got at hand; We'll look into testing it with this specific map, but in the meantime:
Does this behavior change when you alter the detail slider in the map controls? How about when you zoom in and out?
If none of those work, you could try renaming the /Users/<username>/Library/Caches/com.garmin.BaseCamp/CardProductCache/ folder to force BaseCamp to reload that map from your device. If that fixes your issue, I'd very much like to know, as, to my knowledge, we don't generally have problems loading device maps.