920, Once the Hinterlands is cleared the fereldan locks no longer seem to drop. The way you tell if you've reached that point is by checking in with Mother Giselle (in the chantry building or in the gardens, depending on your base). If you ask her how the people are doing 'everywhere else', she will report on the state of folks in Redcliffe, Crestwood and Emprise du Lion. If her Redcliffe one no longer has the 'refugees are starving and freezing' status, but more that they're well fed and comfortable, Hinterlands is cleared. And the Fereldan locks won't drop anymore. So yeah, I think it's a bug to have that situation when you have a quest that relies on the locks.