@tiana_anjara, maybe you will need to download your project as XLSForm and then look at it more closely on this. You should be able to see the skip logics more easily in an XLSForm. Note, there could also be other skips that has been triggered before it reached to A6a and A6b. Check out to see if there are any group skips that has affected this.
You need not worry on this. As long as you have deployed your project with the grid theme and you see then fall back to the default you will still be able to view your project in the grid theme layout. This is something KoboToolbox will improve in the near future.
We have a couple of issues being reported with this case. We do have a GitHub issue for this which we will address in the near future.
But as for now, you could download your project in XLSForm and then upload the same back to the server. That should fix the issue.
The matrix question uses the grid theme layout. This layout is best displayed with Enketo aka web forms. And, Enketo forms are best displayed with devices that has a large screen. PCs and tablets have large screen thus the forms are best displayed in these devices when compared with a smartphone with a small screen.
