The two problems may be unrelated, but this history error did not occur in the previous release.

The issue seems to happen when a player scrolls or moves through entries in the History panel. After the exception occurs, the map freezes and the game cannot be continued normally. Players have been leaving the bot and then re-entering the game as a temporary workaround.

Here is the stack trace:

Exception: java.lang.IllegalStateException
java.lang.Exception
at com.google.common.base.Preconditions.checkState(Preconditions.java:518)
at games.strategy.engine.history.History.getDeltaTo(History.java:111)
at games.strategy.engine.history.History.gotoNode(History.java:127)
at games.strategy.triplea.ui.history.HistoryPanel.gotoNode(HistoryPanel.java:269)
at games.strategy.triplea.ui.history.HistoryPanel.treeSelectionChanged(HistoryPanel.java:257)
at java.desktop/javax.swing.JTree.fireValueChanged(JTree.java:3019)
at java.desktop/javax.swing.JTree$TreeSelectionRedirector.valueChanged(JTree.java:3520)
at java.desktop/javax.swing.tree.DefaultTreeSelectionModel.fireValueChanged(DefaultTreeSelectionModel.java:650)
at java.desktop/javax.swing.tree.DefaultTreeSelectionModel.notifyPathChange(DefaultTreeSelectionModel.java:1120)
at java.desktop/javax.swing.tree.DefaultTreeSelectionModel.setSelectionPaths(DefaultTreeSelectionModel.java:306)
at java.desktop/javax.swing.JTree.setSelectionInterval(JTree.java:2636)
at java.desktop/javax.swing.plaf.basic.BasicTreeUI$Actions.increment(BasicTreeUI.java:4909)
at java.desktop/javax.swing.plaf.basic.BasicTreeUI$Actions.actionPerformed(BasicTreeUI.java:4590)
at java.desktop/javax.swing.SwingUtilities.notifyAction(SwingUtilities.java:1804)
at java.desktop/javax.swing.JComponent.processKeyBinding(JComponent.java:2962)
at java.desktop/javax.swing.JComponent.processKeyBindings(JComponent.java:3010)
at java.desktop/javax.swing.JComponent.processKeyEvent(JComponent.java:2924)
at java.desktop/java.awt.Component.processEvent(Component.java:6353)
at java.desktop/java.awt.Container.processEvent(Container.java:2260)
at java.desktop/java.awt.Component.dispatchEventImpl(Component.java:4958)
at java.desktop/java.awt.Container.dispatchEventImpl(Container.java:2318)
at java.desktop/java.awt.Component.dispatchEvent(Component.java:4790)
at java.desktop/java.awt.KeyboardFocusManager.redispatchEvent(KeyboardFocusManager.java:1829)
at java.desktop/java.awt.DefaultKeyboardFocusManager.dispatchKeyEvent(DefaultKeyboardFocusManager.java:874)
at java.desktop/java.awt.DefaultKeyboardFocusManager.preDispatchKeyEvent(DefaultKeyboardFocusManager.java:1136)
at java.desktop/java.awt.DefaultKeyboardFocusManager.typeAheadAssertions(DefaultKeyboardFocusManager.java:1011)
at java.desktop/java.awt.DefaultKeyboardFocusManager.dispatchEvent(DefaultKeyboardFocusManager.java:839)
at java.desktop/java.awt.Component.dispatchEventImpl(Component.java:4839)
at java.desktop/java.awt.Container.dispatchEventImpl(Container.java:2318)
at java.desktop/java.awt.Window.dispatchEventImpl(Window.java:2671)
at java.desktop/java.awt.Component.dispatchEvent(Component.java:4790)
at java.desktop/java.awt.EventQueue.dispatchEventImpl(EventQueue.java:725)
at java.desktop/java.awt.EventQueue.dispatchEvent(EventQueue.java:702)
at java.desktop/java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:203)
at java.desktop/java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:124)
at java.desktop/java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:113)
at java.desktop/java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:109)
at java.desktop/java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
at java.desktop/java.awt.EventDispatchThread.run(EventDispatchThread.java:90)
Interpretation

The important part is:

History.getDeltaTo
History.gotoNode
HistoryPanel.gotoNode
HistoryPanel.treeSelectionChanged

This indicates that the crash is happening when TripleA tries to move from the current game state to another point in the History tree.

History.getDeltaTo() is likely attempting to calculate which game-state changes must be applied or reversed in order to display the selected historical position. The Preconditions.checkState() failure means that an internal assumption about the history structure is not true.

In practical terms, TripleA may be encountering one of these situations:

the selected history node is no longer connected properly to the current node;
the history index contains an unexpected or invalid state;
the client receives a game update while the user is viewing an earlier history entry;
navigating quickly with the keyboard causes the History panel and game state to become temporarily out of sync.

The lines involving:

JTree.setSelectionInterval
BasicTreeUI$Actions.increment
processKeyBinding

strongly suggest that the user was moving through the History tree with the keyboard, probably using the arrow keys.

The map freezes because the exception occurs on Java’s Swing event-dispatch thread, which controls the interface. Once that thread fails during the history transition, the UI may remain stuck even though the bot-hosted game itself is still running. That would explain why leaving and re-entering restores access: the player reconnects with a fresh client state.

I would describe this as a client-side history-navigation synchronization bug, possibly triggered when viewing history during a live bot game. It does not necessarily mean that the saved game itself is corrupted.