I have been noticing the problem for a couple of updates. To day if got firmware and maps updates for my Garmin 3597LM. Same problem still exists. I have tried to attach a screen shot but not sure how the improved attaching works. BaseCamp route calculation is taking side roads that are not shorter or faster. It does the for both Fastest and Shortest routes. I have been noticing the problem when close to home and ignoring the turn instruction. On a 444 mile round trip I started checking the map and notice the problem at least twice on the trip. The attached screen shows the route taking Leon Ricketts Rd. which is a dirt road. This problem caused much stress on my last trip as I was pulling a trailer.
Darn I can't add an attachment, when I manage attachments drag the file in, I see the file but no way to upload.