Hello All,
I had some worrisome behavior today with a very short flight with the mavic air 2.
My maximum altitude was set to 478ft (although my intentions with this flight was to remain under 300ft)
Return to home slider was set to 216ft
Winds were calm at a reported 3.5mph
I had just completed a flight and had a bit of battery left so decided to return to the air to grab a few photos of the sunset and a bridge.  I had the aircraft positioned about 1000ft away in a hover at 292ft, took a couple of photos, and allowed the craft to automatically enter return to home due to battery level.  It began to come home.  I did not immediately notice (until reviewing the flight log) that during this portion of the flight it slowed and paused several times and began climbing instead. It should not have climbed at all as it was already above the return to home altitude.  It was still making progress home at this point. A few moments later is when I did notice something was not right as the aircraft stopped all forward motion and quickly climbed past 400ft. I began getting altitude warnings (for passing 400ft) and was trying to figure out what was going on.  The climb continued all the way to the max altitude setting of 478ft.  At this point I cancelled the return to home and took manual control of the craft.  It seemed to opperate as expected under manual control.  I then placed it back into return to home flight to see if it would behave normally.  It did not. It again paused forward flight and quickly began to climb bouncing off of the maximum altitude setting.  I then took full control, flew and landed manually.
This entire flight was only 6 minutes and was in eyesight at all times.  I do not know why it would have behaved in this way and I am nervous to fly this craft again if I can not trust the return to home function.  Anybody have any ideas what may have caused this behavior?  Any input appreciated.  

This is a known issue. Were you perhaps returning home flying towards the setting sun? The obstacle avoidance will see the setting sun as an obstacle, so it stops flying home and climbs in an attempt to rise over the 'obstacle'. Of course it cannot rise above the sun, so you get a 'rinse & repeat' operation going on.

it slowed and paused several times and began climbing instead
Another one of these?
Was there much snow around?

Thank you Geebax!  Yes I was flying toward the setting sun.  I will keep this in mind for future flights!

Labroides Posted at 2-20 18:03
it slowed and paused several times and began climbing instead
Another one of these?
Was there much snow around?

Thanks.  Yes there was snow

Geebax Posted at 2-20 17:59
This is a known issue. Were you perhaps returning home flying towards the setting sun? The obstacle avoidance will see the setting sun as an obstacle, so it stops flying home and climbs in an attempt to rise over the 'obstacle'. Of course it cannot rise above the sun, so you get a 'rinse & repeat' operation going on.

Thinking about this more, If this were the case would I not have gotten an obstruction warning on the RC? And why would manual flight not be affected by this?

Geebax Posted at 2-20 17:59
This is a known issue. Were you perhaps returning home flying towards the setting sun? The obstacle avoidance will see the setting sun as an obstacle, so it stops flying home and climbs in an attempt to rise over the 'obstacle'. Of course it cannot rise above the sun, so you get a 'rinse & repeat' operation going on.

Thinking about this more, If this were the case would I not have gotten an obstruction warning on the RC? And why would manual flight not be affected by this?

A few users are seeing this behavior lately. We don't know an exact cause yet. The two best guesses are sunlight ahead with or without reflection and humidity/cold. The RTH process can behave differently from normally controlled flight by design.

BGulrud Posted at 2-20 18:06
Thanks.  Yes there was snow

There have been a few similar cases in the last month.
For now it's an unsolved mystery.
The flight data doesn't give any conclusive explanation but snow seems to be a common factor.