2.1.392 Part 1 Section 17.15.1.16, caption (Single Caption Type Definition)

a.   The standard allows strings of unbounded length for the name attribute.

Word allows strings of length at most 255 for the name attribute.

b.   In the standard, the heading attribute is described with specific semantics for values 1 through 9.

If the heading attribute is present, Word reads the value as zero and incorrectly displays autogenerated captions.

c.   The standard says the noLabel attribute controls whether labels are included in automatically generated captions.

Word ignores the noLabel attribute and instead uses the value of the chapNum attribute.