StackViewController removeViewControllerAtIndex issue

[cikelengfeng]

Hi!
when I remove several viewController from StackViewController by removeViewControllerAtIndex ,and set animated to YES,I will remove only one VC.
and set animated to NO, I will remove correctly.
is this a bug?
when animated,the stack was been locked,then I can not remove next VC,is this right?
----------update------------
useful log
2013-05-20 15:51:35.883 下厨房菜谱[9987:907] [DEBUG](-[XcfNavigationController removeViewControllerAtIndex:animated:]) - stack after remove (
"XcfProfileViewController: 0x1da8ab40>",
"XcfProfileViewController: 0x1da05a10>",
"XcfDishDetailViewController: 0x1dc4afe0>"
)
2013-05-20 15:51:35.884 下厨房菜谱[9987:907] [DEBUG](-[XcfNavigationController removeViewControllerAtIndex:animated:]) - navigation bar items after remove (
"UINavigationItem: 0x1da96fd0>",
"UINavigationItem: 0x1db73290>",
"UINavigationItem: 0x1dc4e5a0>"
)
2013-05-20 15:51:35.886 下厨房菜谱[9987:907] [DEBUG](-[XcfNavigationController removeViewController:animated:]) - will remove XcfDishDetailViewController: 0x1dc4afe0>
2013-05-20 15:51:35.890 下厨房菜谱[9987:907] [DEBUG](-[HLSAnimationStep addObjectAnimation:forObject:]) - No object to animated
2013-05-20 15:51:35.891 下厨房菜谱[9987:907] [DEBUG](-[HLSAnimationStep addObjectAnimation:forObject:]) - No object to animated
2013-05-20 15:51:35.893 下厨房菜谱[9987:907] [DEBUG](-[HLSAnimationStep addObjectAnimation:forObject:]) - No object to animated
2013-05-20 15:51:35.894 下厨房菜谱[9987:907] [DEBUG](-[HLSAnimationStep addObjectAnimation:forObject:]) - No object to animated
2013-05-20 15:51:35.896 下厨房菜谱[9987:907] [DEBUG](-[HLSUserInterfaceLock lock]) - Acquire UI lock
2013-05-20 15:51:35.897 下厨房菜谱[9987:907] [DEBUG](-[HLSViewController viewWillDisappear:]) - View controller XcfDishDetailViewController: 0x1dc4afe0>: view will disappear, animated = YES
2013-05-20 15:51:35.898 下厨房菜谱[9987:907] Umeng: (logPageView) XcfDishDetailViewController 10 seconds
2013-05-20 15:51:35.899 下厨房菜谱[9987:907] [DEBUG](-[HLSViewController viewWillAppear:]) - View controller XcfProfileViewController: 0x1da05a10>: view will appear, animated = YES
2013-05-20 15:51:35.900 下厨房菜谱[9987:907] [DEBUG](-[HLSViewController viewWillAppear:]) - View controller XcfProfileDishesViewController: 0x1db74c30>: view will appear, animated = YES
2013-05-20 15:51:35.902 下厨房菜谱[9987:907] [DEBUG](-[XcfNavigationController removeViewControllerAtIndex:animated:]) - stack after remove (
"XcfProfileViewController: 0x1da8ab40>",
"XcfProfileViewController: 0x1da05a10>",
"XcfDishDetailViewController: 0x1dc4afe0>"//this VC should be removed,but failed
)
2013-05-20 15:51:35.903 下厨房菜谱[9987:907] [DEBUG](-[XcfNavigationController removeViewControllerAtIndex:animated:]) - navigation bar items after remove (
"UINavigationItem: 0x1da96fd0>",
"UINavigationItem: 0x1db73290>"
)