Pandoc: Output two sumation signs in equal height in Word 2010

Question

I need to output some complex equations in Word 2010 (docx). To do so I write most of the equations in tex and use pandoc to translate them as Word formulas.

However I have a problem with the following tex equation:

\sum_{m=1}^\infty\sum_{n=1}^\infty

In Word the resulting two summation signs are not of the same size but the latter is smaler than the first one. Is there any workaround to solve this?

I would deeply appreciate any help.

Thank you

Andy

Edit:

It was a bug, I filed it and John already fixed it (see https://github.com/jgm/pandoc/issues/896)