Sounds like your folio has a missing orientation or a corrupted file. Folio
will not show up on the iPad if in your dual-orientation folio one article
is missing one orientation or if two articles share the same name.
For the first one the folio producer editor in the online tool will show a
warning sign when you try to look at the orientations.
We've had this problem, and the way around we were using is to publish your folio, but set it as private - this way you can proof without it going anywhere it shouldn't
apparently a fix was rolled out for this somewhere, but if it's still happening then it's back to the drawing board
but Publish was working for us
Thanks Johannas and Kletsel for pointing me in the correct path.
It was indeed an orientation related problem.
Previously, when I made a visual check of all the articles, they all had a single orientation (portrait). But, after I read your answers, I took a peep at the online editor, and when I switched back from List view, which I'm forced to use due to the buggie scrolling behavior of the Thumbnails view with Right Edge Binding folios, to Thumbnails view, I found a disturbing behavior with the cover article that I didn't noticed before.
When I opened the Relink dialog of this article in the Folio Builder panel, it contained a garbage string in the landscape path. After I erased it the evasive folio finally showed up.
In conclusion, there are 3 issues:
1. Does anyone have any idea to the origin of the garbage string?
2. There's an unresolved editor scrolling issue with the Thumbnails view display of Right Edge Binding folios. Is it going to be fixed (soon)?
3. The orientation warning shows up only in Thumbnails view but not in the List view, and even then, you'll stumble on it only if you check both orientations.
(1) How about adding a general orientation problem alert for both views?
(2) In List view, it will be very helpful (at least for me) if we can have an orientation indication column with H, V, or H+V indication for the article orientation.