Excel 2007 - "Snap To Grid" doesn't work on same grid line
 

A problem recently occurred on a spreadsheet I have worked with for months.
Vertical lines changed to slightly angled lines when moved or altered. Turns
out that I can snap-to on the grid intersection on the first end-point, but
not the second if it is on the same grid line - horizontal or vertical. The
second snap is consistently "offset" to the side of the intersection. Any
ideas?

FYI - borders still align as usual.