the preview of the form is as follows https://enketo.getodk.org/preview?form=https://xlsform.getodk.org/downloads/7otkms8b/totest.xml
As you can see in the attached snip, when the w10 is used so that there are only 10 cells in a row, the grid ends up having 11 cells in the first row.
Likewise, when the w9 is used so that there are only 9 cells in a row, the grid ends up having 10 cells in the first row.
IT works perfectly as expected up to w8. Can't understand why w9 and w10 add and extra cell in top row.