The Mavic 2 senses and actively attempts to avoid obstacles during automatic Return To Home.  The Mavic 2 RTH obstacle avoidance works as follows:

• The Mavic 2 slows down when an obstacle is sensed.
• It will stop and hover, then fly backward and ascends upwards until no obstacle is sensed.
• Next the RTH process resumes and the Mavic 2 drone will return to home point at the new altitude.
  

Note: The Vision Sensors won’t work properly in bad light or may not work at all.  When you receive your Mavic 2, it is a great idea to read the User Manual, especially the sections on the Vision Systems, Intelligent Flight Battery and Return to Home Features.  Read these sections a few times.

Excellent tips