..throws an exception in SaxonEE 9.3.01 (?format-integer() picture is not valid?), while the picture string seems to be valid, according to the spec:
"There must be at least one mandatory-digit-sign. There may be zero or more optional-digit-signs, and (if present) these must precede all mandatory-digit-signs. There may be zero or more grouping-separator-signs. A grouping-separator-sign must not appear at the start or end of the decimal-digit-pattern, nor adjacent to another grouping-separator-sign."
A patch is being committed to Subversion for the 9.3 branch.