Conversion stuck in While iteration

Using the source code to convert a file, it seems to be stuck in a while iteration and the conversion hangs.
Debugging seems to show that the segment of the code is:
\Doc\WordprocessingMLMapping\DocumentMapping.cs at line 298.
Basically, it is inside the buildTableGrid method.

It is similar to:
https://sourceforge.net/p/b2xtranslator/tracker-doc2x-maintenance/141/ 


