Why does AutoCorrect turn italics into underlines, and ignore underscores?

Under AutoCorrect options, it clearly shows: Automatic bold, /italic/, -strikeout- and underline

When I apply Autocorrect to an older document, it completely ignores all the words inside /slashes/. It makes asterisks bold and underscores into underlined text, but absolutely will not make italics. Only if I type new text, and add slashes, will it turn them into italics. It will not touch the preexisting text.

I believe it has to do with the fact that your files are “older documents” – a crucial bit of information that you wisely supplied!

My hunch (I can’t check this, but someone might confirm) is that the version of LibO that you created these files in had the set of autocorrect options that “work”.

You could try this on one doc: open a new file in Writer, and copy/paste the whole contents of the older file into this new one (CTRL+A to select all, of course). If I’m right, then in the new document the AutoCorrect options will work as (now) expected.

(This is what happened with a recent table formatting bug, anyway! I’m just extrapolating to your case.)

Nope. I appreciate the try, but once again all that does is change the font.