Define.xml not generated from master spec XLSX

I am producing an SDTM master spec xlsx doc automated via ODS EXCEL which should produce a native xlsx file for define creation in 2.2.0.

When I try feed in the xlsx spec, pinnacle 21 crashes and no define generated. When i open the XLSX in excel and 'Save As' to another file name without alteration to the content and feed back into Pinnacle 21, the define is created no problem. Is there a known issue using specs created via eg ODS EXCEL directly?