Deviating from route, re-calculates directly to final destination point

I created a running course in Garmin Connect, and sent it to my FR955. On the watch, I enabled the 'Use Map' option, so it can re-calculate the course when deviating. When I was at about 20% of the course, I deviated a bit. Then the watch started to re-calculate. But instead of re-calculating to the original route, it re-calculated shortest route directly to the final end point. Why does this happen? How can I let the watch re-calculate just to the remainder of the orginal course instead?