Borders Disappear When Hiding Columns

I have a worksheet on which I have hidden most of the rows (1-2000 still
show) and most of the columns (A-H still show). When I format the borders of
the "showing" cells, the borders in column H do not appear - the cells remain
all white with no borders showing. If I unhide the hidden columns to the
right of column H, the borders in column H show up normally. There is no
conditional formatting of any kind on this sheet.

Has anyone seen this behavior before, and do you understand why it's
happening?

I'm still stuck with Excel 2003 and Windows XP here at work.

Thanks,

Eric