This issue exists with MacDraw Pro 1.0v1 with the EPSF XTND translator 1.0
The following steps recreate the issue:
1. Import or paste a bitmap with transparent pixels into MacDraw Pro
2. Draw a square or other object, fill with a color and place behind the bitmap. The filled object should be visible through the bitmap.
3. Save As to an EPSF file. Open the EPSF file and print a color separation.
The bitmap will mask out the colored object underneath, as if the transparent pixels were white. There is no current workaround for this issue.