We have a few Portal mapping apps that we are using, and with my personal Samsung Galaxy 6S, the pan works just fine. With my work phone, the Samsung Galaxy 9, the pan option does not work. Unfortunately, there are several other Samsung Galaxy 9 phones in our organization.
The only wild guess I can make is that it may be related to the Galaxy 9's curved screen. This may not be the issue, it's just a guess.
Has anybody had issues with panning Portal maps?
We had this issue recently with a Chrome browser on Samsung Galaxy S9. We weren't using Portal we were using our own home-grown site with ArcGIS Server map services. We switched to the Samsung browser and it worked - that time. We have the issue again on another phone and switching to the Samsung browser isn't helping this time. I will reply again if I find a solution . . . . .
I just wanted to add info to this thread about my experiences. I'm running a 10.6 ent. portal. My sites don't pinch zoom or pan with a finger on Google Pixel and Samsung s8-10 phones. Seems to work on all iphones. Working on upgrading all my servers to 10.7 for a different issue, maybe the stuff will work on the upgraded portal maps.
My cruel luck that the director of my department just happens to have a Google Pixel. I'm offering to just buy him a new iphone, as much as I like pixels.