The Desktop method is only for Driving directions.
For Android Maps, there is no special reporting tools for Directions, to the best of my knowledge.
Thus we have to use Send Feedback in Maps. The best is when the suggested direction is show in the screen, so that a screen shot will be included in the feedback.
The only questions is how to invoke Send Feedback without leaving the screen. There are two ways, so far:
Enable “Shake to Send feedback” in Maps settings. Then shake our mobile when needed.
When we slide our finger from the left edge towards the right, the Maps Menu should open (in Android Maps), then choose Send Feedback.