No, your eyes aren’t playing tricks on you. The grid lines don’t align with the row headers. It is very slight on smaller forms, but forms with hundreds of rows compounds the issue. The further down the grid, the more of an issue the offset is.
If you have ever seen this issue and pulled your hair out trying to figure out why it happens with some users and not others, fixing it is embarrassingly (now that I know) easy. Change the zoom in IE back to 100%!
Take a look at the bottom right area of IE. If you see that the zoom is NOT 100%, select the View / Zoom / 100% menu.
Hopefully this will save you some time if you ever run accross this issue.