I've seen this message mentioned in several past posts but I'm still looking for the reason it pops up and for potential solutions.

This one occurred after deviating from the planned route to take a different way home. I received numerous u-turn instructions before this message and then the navigation quit. Since there were several perfectly valid alternate routes home I'm surprised the Zumo did not recalculate and give me one of them. From what I've read, it may trigger this error after a certain number of u-turn instructions and I certainly had a lot of them. There were no shaping points between where I left the route and where I would rejoin. This has also happened when pulling off a route just slightly, such as into a parking lot. In those cases, restarting the route seems to work fine.
This route was created in BaseCamp using City Navigator North America NT 2024.1, same as the device. Routing is set for faster time and avoidances are unchecked. The Zumo XT software version is 6.50. Garmin technical support, usually good, could not come up with an answer and told me to use Explore. Not happening.
Has anyone figured this out?
Tom