I just converted from a trial to paid license. My trial version worked fine. The margins adjusted to the screen. After I typed in the log key, all my margins are set to end at 6". I checked the settings on the editor tab. It’s set properly.
I then uninstalled and reinstalled with the most recent update. My margins are still 6" and dragging the toggle on the ruler changes nothing.
This wouldn’t be anything inherent to the program itself, or in fact even anything in your preferences, or the project, or even necessarily that text item you are looking at in the binder. 
Right offset indent is strictly per paragraph. So you might somehow have changed all of your paragraphs to have a 6" right indent, and transitioning from the trial is just a red herring in this case. Scrivener won’t update the formatting in your files unless you tell it to, with the Documents/Convert/Formatting to Default Text Style menu command.
But, incidentally, that’s your way out of this pickle. Make sure your settings are correct in the Editor tab, then use that command to fix your 6" indented files. If you think those settings might be wrong in the Editor tab, try dragging the right indent marker all the way to the right. That should reset it to “off” and wrap-to-window mode again.