If this isn't a bug, it violates my expectations of how the app should behave. Logos app for iOS 2.0.2 on an iPad running iOS 5.0.1. The resources in question are both downloaded.
I'm using Carson's "For the Love of God" devotional. Using today (Feb 24) as an example, I touch the "Exodus 7" link which pops up the reference; then I click "Jump to reference" (ESV). When I'm done reading that, I two-finger swipe to return to the devotional. I then jump to the Luke 10 reference. When I'm done reading that, a two-finger swipe takes me back to Exodus 7. I have to do the swipe a second time to get back to the devotional. When I'm done reading Job 24, it takes 3 two-finger swipes to return to the devotional.
I've spent a fair amount of time thinking about why it would work this way in the event that this is "as designed". But I can't come up with any scenario where this makes sense or would match a user's expectations. The previous resource / location at every point was the devotional; so a single two-finger swipe should take me back there.
Donnie