bug, possibly: bottom border in table cell rendered wider than to p border for same width value

[TS...@uk.imshealth.com]

I've experienced problems getting the same width border on the top and
bottom of my table cells; the bottom is always fatter than the top (isn't it
always so...). I've checked and the width value is that same (1 pt) and the
cells above and below don't have any border.
Has anyone else had this problem?

cheers,
Tom SW