A family of Microsoft word processing software products for creating web, email, and print documents.
If heading numbers display when you display nonprinting marks, check if one or more heading numbers have been formatted as hidden text.
Note that with nonprinting marks displayed, you will see a dotted underline beneath text which is formatted as hidden.
Click a heading number to select it. Pressing Ctrl+Shift+H should remove the hidden format. The command is a toggle. See the screen shot below.
If this works, repeat for the other numbering levels / heading levels.