We print almost everything to PDF (using the stock, OOTB DWG to PDF.pc3 file). We also use a fair amount of Mtext background masking, and background masking applied to Civil 3D labels.
When using the PLOT command, in many most cases, at least one background mask per page comes out with some sort of defect. Anything from a gray border where the edges of the masking should be to a complete blackout of the area that should be masked. (And the defect is sort of random in nature. On an initial print, it may show up on Annotation "a", one the next print, it may show up on Annotation "b")
When we take the same drawings, add them to a sheet set, and publish the sheet set to PDF - the masking problems go away. I've always assumed that "Publish to PDF" uses the same driver as the PC3 file, but there is certainly something different going on.
Anyone else ever notice this?