My Nexus 5 (with the latest Android Tablo software 1.0.21) only plays Tablo recordings in landscape (auto-rotates), even when auto-rotate is turned off in the main Android settings…so I think something is up with your phone.
I am having the same problem on my Moto G phone. Before this update, I could play shows in landscape and portrait in both directions, for a total of four different ways. With this current update, it is landscape only and only one orientation (with volume and power buttons on top).
I submitted a ticket on this issue to help get it resolved.