Global Mapper v25.0

GM scripting: reproject/Export raster sets two no_data/background values

In my script, I set:

SET_BG_COLOR COLOR=(255,255,255)

I reproject my input LCC GeoTiff (that has a background value of 255) to Google's Web mercator.

I use export raster to save the results to a new file.

Then I open the exported image in a 3rd party software and can see two different background values. The original, plus a new outer ring of zeros (0). How do I export the data so that there is only one background value? Also, I can't use the "BG_TRANSPARENT=YES" as that will create an alpha channel--besides the output still has two different values for background (0 and 255) which other basic 3rd party image viewers do not use.

Is there a way around this?