Ok I figured this out. In SharePoint I have four lists with the same field name on all four lists. One parent list the field name imports into tableau as a whole number and the same field from the other lists import as a string. I was converting the field to a whole number using the convert option in Tableau. When I did that if somebody added a new item to one of the child lists Tableau could not, for whatever reason, make the conversion on new items.
The solution was to make a copy of the child field(s) make a calculated field and wrap the int function around the value and it worked. Sheesh.