The problem: when you edit a 360 photo to adjust the highlights, or increase clarity, it will often lead to a seam between the left edge and right edge of the photo. One solution is to use an app called AntiSeam360 by Stephan Baum (download here). Thanks Stephan! Here is the tutorial:
Note: Anti-Seam 360 is available only on Android for now.
Another way is to use Google Photos to edit the photo. With Google Photos, you can edit a 360 photo any way you like, and the edit will not create a seam line. Moreover, the edited 360 photo will retain its 360 metadata. BTW Google Photos is available on iOS and Android. It’s one of the reasons Google Photos is my favorite editor for mobile editing of 360 photos. Incidentally, there are other benefits of Google Photos for 360 photos: