Did you remove italics from the TOC4 style (that's not the same
as the Heading 4 style) in Format | Styles and Formatting?

Frank Drost wrote:

Hi all,

At one time I have created a table of contents. The table looks fine, but I
have now decided to change the style of my heading 4 (from italic to normal).
When I follow the manual in how to update my table of contents (open master
document, normal view, click somewhere in table of contents and then press
F9), I do get the pop-up window asking me whether to update the page numbers
only, or update the whole table. When I click on update the whole table, I
see that Word is working on something, but when it is done, the heading 4
link is still in italic in my table of contents (where as the heading 4 text
in my paper is still in normal text).
Have I forgotten to do something? Did I do something wrong?

Does anyone have an idea?

Thanks.