After troubleshooting with Sumo support, their suspicion is that the Custom HTML container is placed on top of the page when in Mobile.
They say, “I believe your theme is moving the Custom HTML container up that contains your Inline Form. Your Sumo Inline Form is an embedded form, meaning it will display wherever the container (it is embedded on) is positioned on the page.”
So my question: Is that the case with the GeneratePress theme, and can I do anything about that?
GP wouldn’t effect the placement of the form within the content, it doesn’t even know it exists.
Possible issues outside of a problem with the plugin / plugin setup:
1. Caching – suggest clearing and disabling any server / plugin caches.
With all these tests you would need to clear browser caches or check in private / incognito browser.