Voltas on multiple staves do not anchor properly

1. Create (or open) a multi-staff score
2. Drag-and-drop a first-ending volta onto the top staff (any measure but the first)
3. Drag-and-drop a first-ending volta onto each remaining staff. Notice that the anchor lines point to the top staff.
4. File > Save
5. File > Reload

Expected behavior: Voltas should not change after reload

Actual behavior: All the voltas from step 3 above now start at measure 1 and extend to the measure you originally placed them.

(Tested using r.1644, Windows XP)