I just engraved on this stainless steel tumbler using the F1 Ultra and the RA2 Pro.  When the engraving started, it was fine, but by the end of the process, it didn't engrave as completely through the coating.  I've attached two photos so you can see the difference.  Any idea why it would do this?  I've also attached the XCS file so you can see how I had it set up.