Original report was in "Bug 49115 - UI: document saved from Page Preview shows empty grey UI background instead of page preview", and that tis one might be related. When I try to export an empty sheet with with "LibreOffice 3.5.3.1 (RC1) English UI/ German Locale [Build-ID: 21cb047-d7e6025-9ba54fc-b4a51a8-f42372b] on German WIN7 Home Premium (64bit), no PDF will be created, instead "Error saving Document. Write Error. The file could not be written". Cell borders will heal the problem, but not cell background Inconsistent compared with other LibO applications and compared to printing, what works without error message, but wrongly; expected would be print of page with heading and footer, actual no printout. Same with LibO 3.3.3 and OOo 3.3, so inherited from OOo Pls also see "Bug 43012 - Printing of sheets without invisible contents should be suppressed with unchecked 'Include Output of empty pages'"
Confirmed with: LOdev 3.5.3rc1+ Build ID: 51648779-22e3d74-d554af7 Windows 7 Professional SP1 64 bit
When you use LibreOffice as a server converting documents to PDFs, then this bug is not of importance "trivial", IMHO.
*** This bug has been marked as a duplicate of bug 42166 ***