"view 3d structure" maps spurious structures to sequences

Something seems to have broken with the structure chooser dialog.

1. import example feredoxin alignment (uniref50.fa)
2. select all sequences
3. right click and select 'view 3d structure...'
4. 4 structures should be highlighted. Hit view to view them.

The chooser will say that dbrefs are being retrieved for 4 sequences. After this, a 'Sequence names updated' window appears. Contents are:
Your sequences have been verified against known sequence databases. Some of the ids have been
 altered, most likely the start/end residue will have been updated.
 Save your alignment to maintain the updated id.

Q93XJ9_SOLTU SEQUENCE NOT %100 MATCH
FER1_SPIOL SEQUENCE NOT %100 MATCH
FER2_ARATH SEQUENCE NOT %100 MATCH
FER1_MAIZE SEQUENCE NOT %100 MATCH
Q93XJ9_SOLTU SEQUENCE NOT %100 MATCH
FER1_MAIZE SEQUENCE NOT %100 MATCH
FER1_SPIOL SEQUENCE NOT %100 MATCH
FER2_ARATH SEQUENCE NOT %100 MATCH
FER1_MAIZE HAS 52 PREFIXED RESIDUES COMPARED TO PDB
FER1_MAIZE HAS 0 PREFIXED RESIDUES COMPARED TO PDB
FER1_MAIZE SEQUENCE NOT %100 MATCH
FER1_MAIZE SEQUENCE NOT %100 MATCH
FER1_MAIZE SEQUENCE NOT %100 MATCH
FER1_MAIZE SEQUENCE NOT %100 MATCH
FER1_MAIZE SEQUENCE NOT %100 MATCH
FER1_MAIZE SEQUENCE NOT %100 MATCH
FER1_MAIZE SEQUENCE NOT %100 MATCH
FER1_MAIZE SEQUENCE NOT %100 MATCH
FER1_MAIZE SEQUENCE NOT %100 MATCH
FER1_MAIZE SEQUENCE NOT %100 MATCH
FER1_MAIZE SEQUENCE NOT %100 MATCH
FER1_MAIZE SEQUENCE NOT %100 MATCH
FER1_SPIOL SEQUENCE NOT %100 MATCH

Eventually structure view appears, but superposition does not reliably occur.

Looking at the RESNUM features, FER1_MAIZE seems to have mappings to additional structures, even though they are not actually viewed.

If 'Fetch db refs->Standard DBs' is performed before step 2, then no 'Sequence names updated' window is shown, and no spurious PDB mappings appear on the alignment.