On a windows machine at work we have the same issue mentioned in http://osdir.com/ml/msysgit/2010-10/msg00165.html.
Running a command like "git status" repeatedly, it will often produce no output at all, while other times giving the desired status information.
On #git I was adviced to do "export GIT_PAGER=cat", but that didn't change the behaviour. Then I was adviced to tell the mailing list, which I now do :-)
- Tasslehoff