Route Calculation Error

Today while following a course I created on GC and downloaded to the 5X from GCM, I twice got a "Route Calculation Error." When this happened the watch stopped following the course and reverted back to the map. I was able to reload the course, only to get get the "Route Calculation Error" a mile or so later.

I've previously followed several courses on the 5X without issue. This was my first time following this particular course, so I don't know whether it was something specific to this course, or some other issue. Both times it occurred when I was slightly off course; normally the watch reroutes without issue.

Has anyone else experienced this error?