After installation of KB2977629, ActiveX update by changing version in object tag doesn't take effect without restarting IE11.
This happens only in case the page includes ActiveX controll event handler.
I don't know why this is only published in Japanese but
http://support.microsoft.com/kb/2864032/ja
says the same thing about IE10.
When I found this article at the beggining of this year, I was suffered by this but it was solved with workaround code there.
But this time, it is IE 11 under workaround code is applied.