Sorting Structure Chooser table by Sequence id fails with ClassCastException

Load uniref50.fa, select all sequences, fetch 3D structure data.
A panel of PDB entries is displayed.
All columns appear to be sortable except for the first (Ref Sequence), which throws an error ClassCastException on click to sort by this column.
Exception in thread "AWT-EventQueue-0" java.lang.ClassCastException: jalview.datamodel.Sequence cannot be cast to java.lang.String
at java.text.Collator.compare(Collator.java:304)
at javax.swing.DefaultRowSorter.compare(DefaultRowSorter.java:968)
at javax.swing.DefaultRowSorter.access$100(DefaultRowSorter.java:112)
at javax.swing.DefaultRowSorter$Row.compareTo(DefaultRowSorter.java:1376)
at javax.swing.DefaultRowSorter$Row.compareTo(DefaultRowSorter.java:1366)
at java.util.ComparableTimSort.countRunAndMakeAscending(ComparableTimSort.java:320)
at java.util.ComparableTimSort.sort(ComparableTimSort.java:188)
at java.util.Arrays.sort(Arrays.java:1246)
at javax.swing.DefaultRowSorter.sort(DefaultRowSorter.java:607)
at javax.swing.DefaultRowSorter.setSortKeys(DefaultRowSorter.java:319)
at javax.swing.DefaultRowSorter.toggleSortOrder(DefaultRowSorter.java:480)
at javax.swing.plaf.basic.BasicTableHeaderUI$MouseInputHandler.mouseClicked(BasicTableHeaderUI.java:112)
at java.awt.AWTEventMulticaster.mouseClicked(AWTEventMulticaster.java:270)

Other columns remain sortable until (it appears) the panel loses and regains focus, and then they fail with the same error.