Testcase distilled from http://www.microsoft.com
The problem seems to be that the last cell in each row have an "excessive" COLSPAN value.
I have added BORDER=1 to make the cell boundaries visible.

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The following table is exactly as above, but I have removed COLSPAN for the last cell in row 1 and 2,
and changed COLSPAN=4 to COLSPAN=3 in the last row.

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