Recently the rth stopped working.
When I activate rth it starts ascending but it doesn’t stop on rth altitude it continues to go higher until maximum altitude is reached.
Then I get an error message that maximum altitude is reached and it just hovers, never returns.
So I have to fly it back manually.
I tried to reinstall the app but no difference.
Latest firmware is installed.

Sounds like the downward or forward sensors are broken or dirty.  Try cleaning them or disabling them and see if it works then.
Its trying to avoid an 'obsctacle'

Hi, thanks for reaching DJI Forum. We do apologize for the troubles you had with your DJI Mavic Pro. May we ask for the brand or make of your mobile device? Also I'd like to know the version of your aircraft and the remote controller. We're here to help you. Thank you.

Hello,
Thanks for Your quick reply.
I will check the sensors.
I get no warnings and everything else works just fine.
I attached a screenshot of the sw versions.
Many thanks for all support.

My device is a IPhone 8 Plus.

Check out your TXT flight log to see if it explains what happened. You can upload and view it online here. If you'd like others to comment on your flight log, then please post a link back here after you upload it.

msinger Posted at 2018-8-16 09:06
Check out your TXT flight log to see if it explains what happened. You can upload and view it online here. If you'd like others to comment on your flight log, then please post a link back here after you upload it.

Ok, will install Itunes and try to retrieve the file and post the link.
Thanks :-)

Tajjson Posted at 2018-8-16 09:17
Ok, will install Itunes and try to retrieve the file and post the link.
Thanks :-)

Would your craft have been facing into the sun when it was ascending ?

If the sun goes down and facing the drone then the drone conceder it as an obstacle, therefore it will ascend the maximum altitude that can avoid the sun to return back! that is never can.

You need either to bring it manually through different directions that not facing the sun, or by closing the obstacle avoidance in the settings.

It was cloudy, so not sunny at all here right now in Uppsala Sweden :-)
I have tried rth several days in a row now so its not the sun issue.
I have had some complaints since day one saying left fw sensor malfunction, but recently I did not get these warnings.
I get no error messages at all now. it just keeps climbing and climbing.
I have tested at least 10 times on different occasions, and I get the same issue every time.

heres the link to one of the flightlogs
http://www.phantomhelp.com/LogViewer/F63DCZBYAIW2BPVPWEKH/

Weird. VPS is working so downward sensors are OK. Only thing I can think of is your forward sensor error is probably linked to this. When you fly close to an object, do you get the obstacle avoidance warning? If not, that's probably your answer.

Paul_IA Posted at 2018-8-16 09:59
Weird. VPS is working so downward sensors are OK. Only thing I can think of is your forward sensor error is probably linked to this. When you fly close to an object, do you get the obstacle avoidance warning? If not, that's probably your answer.

Yes, Agree. Very weird.
The forward sensors seems to work just fine, I get all the beeps and warnings if I fly towards a tree or something in the way..

Tajjson Posted at 2018-8-16 09:48
heres the link to one of the flightlogs
http://www.phantomhelp.com/LogViewer/F63DCZBYAIW2BPVPWEKH/

Nothing wrong in the flight log.

Possible either an obstacle avoidance issue or the FW.

Ahmed Hussain Posted at 2018-8-16 10:24
Possible either an obstacle avoidance issue or the FW.

I get no sensor warnings at all. I think this started after latest fw upgrade, but I am not 100% sure..

Tajjson Posted at 2018-8-16 10:33
I get no sensor warnings at all. I think this started after latest fw upgrade, but I am not 100% sure..

Ascending higher than the RTH altitude is a possible sign of obstacle avoidance issue.

Yes, could be the firmware.

Tajjson Posted at 2018-8-16 08:53
My device is a IPhone 8 Plus.

Oh crap, he's using an iPhone, now where is DJI going to point the finger?

Just to rule things out, do some tests.

Disable "Obstacle avoidance in RTH" in the menu and test.

Then disable all the sensors and try an RTH.

Tajjson Posted at 2018-8-16 09:45
It was cloudy, so not sunny at all here right now in Uppsala Sweden :-)
I have tried rth several days in a row now so its not the sun issue.
I have had some complaints since day one saying left fw sensor malfunction, but recently I did not get these warnings.

Ok was just trying to rule that one out. Can’t believe it’s cloudy in Uppsala, I’ve been there 3 times this Summer , weather was incredible, managed to shoot this video, you might know the place. Excuse me for going off topic.

If you have not already tried, it might be worth changing RTH from 70-meters down to say 40-meters.  Go for a test flight in a clear area with nothing higher than 20-meters.  Then try a RTH.   

well that was strange

Have you tried a FW re-install ? I would also give that a try if not.