Cant export an all white alpha chanel

I am trying to create a packed texture -  Color_AO 

In some cases I don’t need an AO and so I want to pack the alpha channel with all white so my in game shader will still render correctly 

When I plug a uniform white into the alpha and export the alpha channel is not exported 

It will only export the alpha channel when I have some value range in whats being plugged into the Alpha of the RGBA Merge node 

I am exporting as TGA in RAW color space