The following steps recreate the problem:
1) In MacDraw Pro 1.0v1, create a rounded rectangle and an oval
2) Fill them with any fill pattern
3) Save out as an EPSF file
4) Open the EPSF file as a new document
5) Zoom out
The fill pattern may not be visible on the screen. Diagonal line-type fill patterns seem to disappear at about 50% zoom level. Dark gray fill patterns disappear at about 25% zoom level.
The EPSF will print correctly, however. This is only a screen preview problem.