Cells following a row span are shifted when rendering to CommonMark Markdown 1.2

Markdown doesn't support row spans. When rendering a table containing a cell spanning several rows (rowspan parameter) to markdown/1.2, the following rows have one cell less than the others, so their cells are shifted to the left.

Steps to reproduce

Render the following xwiki/2.1 content to markdown/1.2:

|=a|=b|=c
|(% rowspan="2" %)d|e|f
|g|h

Result

g is rendered under d and h under e.

Expected

The cells stay in their columns (g under e, h under f), e.g. by inserting an empty cell where the spanned cell was.