Happened to me since 1.3.0 I think. FAF Client freezes after a while and remains unresponsive. Can happen basically anytime whether a game is active or not. Error logs keeps pushing this out:
Exception in thread "JavaFX-Launcher" java.lang.IllegalStateException: Task must only be used from the FX Application Thread
at javafx.concurrent.Task.checkThread(Task.java:1220)
at javafx.concurrent.Task.progressProperty(Task.java:983)
at com.faforever.client.ui.taskbar.WindowsTaskbarProgressUpdater.onActiveTasksChanged(WindowsTaskbarProgressUpdater.java:57)
at com.faforever.client.ui.taskbar.WindowsTaskbarProgressUpdater.lambda$afterPropertiesSet$1(WindowsTaskbarProgressUpdater.java:48)
at com.sun.javafx.collections.ListListenerHelper$SingleInvalidation.fireValueChangedEvent(ListListenerHelper.java:126)
at com.sun.javafx.collections.ListListenerHelper.fireValueChangedEvent(ListListenerHelper.java:73)
at javafx.collections.ObservableListBase.fireChange(ObservableListBase.java:233)
at javafx.collections.FXCollections$UnmodifiableObservableListImpl.lambda$new$0(FXCollections.java:963)
at javafx.collections.WeakListChangeListener.onChanged(WeakListChangeListener.java:88)
at com.sun.javafx.collections.ListListenerHelper$SingleChange.fireValueChangedEvent(ListListenerHelper.java:164)
at com.sun.javafx.collections.ListListenerHelper.fireValueChangedEvent(ListListenerHelper.java:73)
at javafx.collections.FXCollections$SynchronizedObservableList.lambda$new$0(FXCollections.java:1217)
at javafx.collections.WeakListChangeListener.onChanged(WeakListChangeListener.java:88)
at com.sun.javafx.collections.ListListenerHelper$SingleChange.fireValueChangedEvent(ListListenerHelper.java:164)
at com.sun.javafx.collections.ListListenerHelper.fireValueChangedEvent(ListListenerHelper.java:73)
at javafx.collections.ObservableListBase.fireChange(ObservableListBase.java:233)
at javafx.collections.ListChangeBuilder.commit(ListChangeBuilder.java:482)
at javafx.collections.ListChangeBuilder.endChange(ListChangeBuilder.java:541)
at javafx.collections.ObservableListBase.endChange(ObservableListBase.java:205)
at javafx.collections.ModifiableObservableListBase.add(ModifiableObservableListBase.java:155)
at java.base/java.util.AbstractList.add(AbstractList.java:111)
at javafx.collections.FXCollections$SynchronizedList.add(FXCollections.java:1067)
at com.faforever.client.task.TaskService.submitTask(TaskService.java:47)
at com.faforever.client.mod.ModService.afterPropertiesSet(ModService.java:114)
and then some springframework stuff. Do you need the full stacktrace?