[Dba-office] Interesting Word table problem

A reader sent me a Word document that's comprised of multiple tables
formatted to look like a paper form. He used a table to insert labels and
used the border to create underscores.

Name ____________________________

Where Name and the underscore are two cells in the same row of a table.

When applying the Bottom Border attribute to some of the cells, Word
applies the underscore to all of the cells in the row, instead of only the
selected cell.

All of the cells look exactly the same. I even used Format Painter to
format the culprit cells using a good cell. Eventually, I was able to work
around it, by splitting, underscoring, and then merging the culprit cells
back to a single. But, that shouldn't be necessary and I'd like to know
what caused this.

Has anyone run into this before and resolved it rather than skirting around
it?

Thanks!
Susan H.