Navigation Issues

Yes, had the same issue. Despite having it set to Road profile and to ignore trails etc., it was trying to send me down forest paths.

When re-routing yes.  Tried to send me down a footpath.

Luckily i was near home and was just testing the feature out.

Nothing wrong with the map data, before anyway starts down that path.  I know OSM and have/can edit the data myself.

On-device routing is a mess IMO.

I plan my routes with Komoot and disabled re-calculation; works reasonably well. Basically like my Wahoo Bolt, but in color. *sigh*

Except for roundabouts, which still don't work *slow clap*

Whats up with roundabouts?  They work fine for me.

Can you point to a location where you have problems?

"Lock on road" just effects how the location arrow is displayed. It has nothing to do with routing.

I believe he means turn-by-turn navigation.

Best advice would be to not rely on turn-by-turn navigation and especially don't rely on turn alerts. I've had situations where I've ridden past turns because the navigation was telling me the next turn is over a kilometer away. I've tested it and it's consistent, so it's down to map data.
Best to just keep an eye on the map while you need the assistance. 

Re-routing can be difficult if you're riding through an area that has various different surface types around you. The device will then calculate the shortest route, not necessarily the best one. I've also had situations where the device was telling me to ride for 500 meters and then turn back. But I've never had it mix up terrain types. Are you 100% sure you've the routing mode set to Road Cycling? Did you check whether the road was properly marked as unpaved? 

I'd say it's really more to do with the map data and less with the device itself. Might be worthwhile experimenting with different maps if it's really bothering you. 

Ah - that's good clarification. 

The routing was definitely set to road cycling and avoiding trails and unpaved roads - some of the paths that it was trying to send me down required climbing over walls and riding through farm buildings!

I generally know where I'm going when riding, just happened to be in a totally new area so was relying on the routing and it was a big disappointment!

The Garmin cannot re-route successfully to save your life - it'll faithfully follow a planned route but god help you if you stray off it. It's pretty much unable to choose an intelligent re-route option - lucky if your re-route was a short one and it just might route you straight to your car  but if  you're a couple of kms away and there's a myriad of choices the unit can come up then it can tell you to do another mega marathon ride again. And there's no reroute again button - so that one can choose the best of the worst options. It's situation like that that makes you appreciate the wahoo's setup with ease of loading routes from the phone. When you're lost you can plan a route on the phone and send it to the unit. Phone screen is much larger and easier to plan a route.