Insertion point disappears in outline view of PPt 2007

When typing the content of my presentation in outline view, if I pause for a
second, the insertion point "disappears". If I continue to type, the new text
does not show up either in the outline or on the slide. I can click back in
the outline pane and continue but the insertion point soon disappears again -
sometimes in the middle of a word.

I provide training and support to faculty and staff at a 2-yr college and
one of my faculty members called this morning with the same issue.

I have used the outline pane extensively in multiple versions of PPt
(including 2007) and have never experienced this issue before. Does anyone
know if this is a known issue?