I've had this issue as long as I remember and so does another fellow Daz/Octane user I know. The Viewport doesn't automatically render changes to the scene when rendering. This is very hit and miss. On fresh scenes, it always works. Eventually it will stop auto updating and require a Rebuild Scene for every non-Octane change. To be clear, if I make any changes to an Octane material it will automatically reflect that in the render 100%. However, if I'm changing a pose in a character or some other setting within Daz, it won't work without a rebuild.
I've emailed about this in the past and was recommended to delete the OctaneRender_settings.oczdb. This may have helped temporarily but the problem always returns. I'm posting here to see if anyone else has experienced this and has a solution.
It's obviously not the end of the world to have to rebuild the scene each time. It's a minor inconvenience having to readjust camera focus and wait for the rebuild to occur. Also the option to spot render is removed if you don't notice that the scene didn't update until after the render is finished... although that seems more like the user being at fault
Any help would be appreciated.