RibbonBar crash with animation enabled

Hi,

My application uses a RibbonBar. If I enable animation, the app crashes sometimes after a ribbon button is pushed. Somehow the pointer to the source bits is invalid. Do you have an idea what causes that crash. (using xtt 10.4.2)

Here a call stack:
SomeApp.exe!CXTPCommandBarAnimation::AlphaBlendU(unsigned char * pDest=0x05570000, unsigned char * pSrcBack=0xfeeefeee, int cx=46, int cy=45, unsigned char * pSrc=0xfeeefeee, unsigned char byAlpha='.')  Line 90 + 0x3 bytes    C++
SomeApp.exe!CXTPCommandBarAnimation::AnimateRect(CClientDC & dc={...}, CXTPCommandBarAnimation::CAnimateInfo * pai=0x02fc61c8)  Line 130    C++
SomeApp.exe!CXTPCommandBarAnimation::OnAnimate()  Line 154    C++
SomeApp.exe!CXTPCommandBar::OnTimer(unsigned int nIDEvent=707907)  Line 1264    C++
SomeApp.exe!CXTPMenuBar::OnTimer(unsigned int nIDEvent=707907)  Line 736    C++
SomeApp.exe!CWnd::OnWndMsg(unsigned int message=275, unsigned int wParam=707907, long lParam=0, long * pResult=0x0012fcbc)  Line 2032    C++
SomeApp.exe!CXTPCommandBar::OnWndMsg(unsigned int message=275, unsigned int wParam=707907, long lParam=0, long * pResult=0x0012fcbc)  Line 2345    C++
SomeApp.exe!CWnd::WindowProc(unsigned int message=275, unsigned int wParam=707907, long lParam=0)  Line 1741 + 0x20 bytes    C++
SomeApp.exe!AfxCallWndProc(CWnd * pWnd=0x02efc8e0, HWND__ * hWnd=0x00030c68, unsigned int nMsg=275, unsigned int wParam=707907, long lParam=0)  Line 240 + 0x1c bytes    C++
SomeApp.exe!AfxWndProc(HWND__ * hWnd=0x00030c68, unsigned int nMsg=275, unsigned int wParam=707907, long lParam=0)  Line 389    C++