To reproduce: 
1. Add RadPageView with several pages
2. Set the Text property of page to "Payers & Frequencies"
this.radPageViewPage2.Text = "Payers & Frequencies";
RadPageViewStripElement strip = (RadPageViewStripElement)this.radPageView1.ViewElement;
strip.StripButtons = StripViewButtons.All;
3. Run the project and open the ItemListMenu(available pages) and you will see that name of page is "Payers _Frequencies" 


Workaround: 
1. Subscribe to ItemListMenuDisplaying event and set UseMnemonic property to false: 
void radPageView1_ItemListMenuDisplaying(object sender, RadPageViewMenuDisplayingEventArgs e)
{
    foreach (RadMenuItem listMenuItem in e.Items)
    {
        TextPrimitive textPrimitive = listMenuItem.Layout.TextPanel.Children[0] as TextPrimitive;
        textPrimitive.UseMnemonic = false;
    }
}