Thank you for replying, Sukie. I've been through all your points, documented as follows:
Opening Word in safe mode makes no difference. A search for italics (or bold) in my test document does not find them.
Copying the contents of the document to a new one (what editors call "maggying") makes no difference. I can still not find italics or bold.
I have the most up-to-date build of Office (and Word). I checked the build number against the list at the link you supplied (although I didn't get my update until June 5th, not June 3rd) (screenshot below)
I'm not searching on keyword. I'm simply searching for formatting. So far, it's italics and bold that I've noticed. I've included two screenshots of searches done in particular document in which F&R won't find bold at all, and only finds one instance of italics
(I applied that italics after June 5th). I've included screenshots below of my searches. I've been using this method to search for formatting for years with no issues.
I'm in a huge editors Facebook group (over 6,000 members around the world) and I posted my problem there. Another editor had the same problem earlier this week and hasn't found a solution either.
It seems to be able to find formatting (bold, italics) if that formatting has been applied since JUne 5th. So if I created a new document now, it will find italics and bold. But if I go back to a document I was working on earlier in the week, before June 5th,
and look for italics I created previously or that was created by someone else, it won't find it.
I tested a book manuscript I was working on in 2018 of nearly 200 pages. It would only find italics in tables in appendices at the end. It didn't find italics in the footnotes or in the main text.
Re: search. If I try searching via 'Styles' in the dropdown menu of the "Find" dialogue, the character style Italic is not listed; it is listed in documents where I can find the italics.
Bold search

Italic search

Software version
