Not sure if is is too early to be reporting problems seen in C++.
We have a toolbar button that changes its bitmap depending on state. When the state changes we swap the bitmap returnd by ICommand then get the corresponding ICommandItem from the ICommandBars.Find() method and call Refresh. In previous versions this caused the new bitmap to be displayed on the button.
Not sure if this is an intentional change, or a by-product of the toolbar changes.