I'm running lubuntu 11.10 64 bit, with a pager set for 8 desktops.  I find the pager tends not to redraw properly and randomly adds and removes representation of windows from the pager desktop views.  Also the panel to the right of the volume control doesn't redraw properly after the 'current volume' popup is displayed and then removed.  The first of these problems (and I think, the second too) is due to a bug in misc.c:

get_net_wm_window_type(Window win, NetWMWindowType *nwwt)
    Atom *state;
    int num3;

    bzero(nwwt, sizeof(nwwt));
    if (!(state = get_xaproperty(win, a_NET_WM_WINDOW_TYPE, XA_ATOM, &num3)))

    DBG( "%x: netwm state = { ", (unsigned int)win);

The bzero() call should use sizeof(*nwwt) rather than sizeof(nwwt).  A NetWMWindowType is 4 bytes but on 64 bit a NetWMWindowType* is 8 bytes and so the bzero ends up overwriting 4 bytes it should not.  In pager.c that ends up clearing present_in_client_list and then pager_net_client_list_stacking() ends up freeing PagerTask structs that are still being referenced.

I checked git, and it seems this bug is still present in current source.