Actually, there were no suggested solutions specific to the Lenovo issue, but for the general issue of action bar icons not showing, setting android:showAsAction="always" was suggested - but I'm guessing that this is what the AddToActionBar parameter in AddMenuItem3 does?
The icons are 32x32 per the style guidelines & I haven't seen this issue on any of my devices, nor had it reported by any other users - so I don't think it's happening on a large number of devices.
- Colin.