Can't choose next iteration for "moving" items when releasing an iteration from the planning board

As a person releasing an iteration from the planning board, I can now only select higher-level iterations for my rollover (incomplete) work to be moved into.

Currently we are set up:

Unscheduled
Release 1
•Sprint 1
••Sprint 1 - Team 1
••Sprint 1 - Team 2
•Sprint 2
••Sprint 2 - Team 1
••Sprint 2 - Team 2
Release 2
...

When a sprint is over, if there is rollover, say Sprint 1 - team 2, I currently select the fix version for the the next sprint for that team, i.e. Sprint 2 - Team 2. It seems like now my only choices are "Sprint 1", which doesn't make much sense why it would be set up this way, since it's got to go to the next iteration, which isn't going to be a parent. Before you could choose any unreleased iteration, which seems like a more flexible option. I was under the impression that I was using the fix version/iterations as they were intended. I think I can work around this by initially creating the following sprints in the wrong place, then moving them to the right place in the hierarchy.

We are moving to GH 5.4.1 from 4.4.