After updating to XF 4.0, ContextAction Icons are not shown in Android

I just updated to Xamarin.Forms 4.0.0.497661. Ever since Icons are not displayed for ContextActions in Android. I have not changed the code at all. I am setting the Icon source as follows, which was running till XF upgrade:

                            <MenuItem.Icon>
                                <OnPlatform x:TypeArguments="FileImageSource">
                                    <On Platform="Android, iOS" Value="icon_circled_check_white.png"/>
                                    <On Platform="UWP" Value="Icons/icon_circled_check_white.png"/>
                                </OnPlatform>
                            </MenuItem.Icon>

They were not displayed even if I set the IconImageSource directly.

So what's happening?