Concurrent Error on loading homebrew character

I loaded a character (Kyros) and see this immediately in my console:

7:52:47.916 SEVERE AWT-EventQueue-1 PCGen_Frame1:2939 Uncaught error - ignoring
java.util.ConcurrentModificationException
at java.util.IdentityHashMap$IdentityHashMapIterator.nextIndex(IdentityHashMap.java:715)
at java.util.IdentityHashMap$KeyIterator.next(IdentityHashMap.java:804)
at java.util.Collections$UnmodifiableCollection$1.next(Collections.java:1010)
at pcgen.core.PlayerCharacter.getEquipmentOfType(PlayerCharacter.java:3930)
at pcgen.core.PlayerCharacter.getEquipmentOfType(PlayerCharacter.java:3906)
at pcgen.cdom.enumeration.SkillArmorCheck.calculateMax(SkillArmorCheck.java:145)
at pcgen.cdom.enumeration.SkillArmorCheck.calculateBonus(SkillArmorCheck.java:97)
at pcgen.core.analysis.SkillModifier.modifier(SkillModifier.java:104)
at pcgen.gui2.facade.CharacterLevelsFacadeImpl.getSkillTotal(CharacterLevelsFacadeImpl.java:386)
at pcgen.gui2.tabs.skill.SkillTreeViewModel.getData(SkillTreeViewModel.java:130)
at pcgen.gui2.tabs.skill.SkillTreeViewModel.getData(SkillTreeViewModel.java:50)
at pcgen.gui2.util.treeview.TreeViewTableModel.populateDataMap(TreeViewTableModel.java:199)
at pcgen.gui2.util.treeview.TreeViewTableModel.refreshData(TreeViewTableModel.java:126)
at pcgen.gui2.util.JTreeViewTable.refreshModelData(JTreeViewTable.java:275)
at pcgen.gui2.filter.FilteredTreeViewTable.refreshModelData(FilteredTreeViewTable.java:132)
at pcgen.gui2.tabs.SkillInfoTab$LevelSelectionHandler.valueChanged(SkillInfoTab.java:364)
at javax.swing.DefaultListSelectionModel.fireValueChanged(DefaultListSelectionModel.java:167)
at javax.swing.DefaultListSelectionModel.fireValueChanged(DefaultListSelectionModel.java:147)
at javax.swing.DefaultListSelectionModel.fireValueChanged(DefaultListSelectionModel.java:194)
at javax.swing.DefaultListSelectionModel.changeSelection(DefaultListSelectionModel.java:388)
at javax.swing.DefaultListSelectionModel.changeSelection(DefaultListSelectionModel.java:398)
at javax.swing.DefaultListSelectionModel.setSelectionInterval(DefaultListSelectionModel.java:442)
at pcgen.gui2.tabs.SkillInfoTab$LevelSelectionHandler.run(SkillInfoTab.java:298)
at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:209)
at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:641)
at java.awt.EventQueue.access$000(EventQueue.java:84)
at java.awt.EventQueue$1.run(EventQueue.java:602)
at java.awt.EventQueue$1.run(EventQueue.java:600)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.AccessControlContext$1.doIntersectionPrivilege(AccessControlContext.java:87)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:611)
at pcgen.gui.PCGen_Frame1$WaitCursorEventQueue.dispatchEvent(PCGen_Frame1.java:2934)
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:269)
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:184)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:174)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:169)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:161)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:122)