2.1.341 Part 4 Section 2.13.5.20, ins (Inserted Run Content)

For additional notes that apply to this portion of the standard, please see the notes for customXml, §2.5.1.5(a); comment, §2.13.4.2(b, c); cellDel, §2.13.5.1(a); oMathPara, §7.1.2.78(a).

a.   The standard allows nested insertions.

Word does not support nested insertions.

b.   The standard states that the author attribute is required, but the prose defines its behaviour when omitted.

Word behaves according to schema - the author attribute is required.