There is a little text corruption issue that pops up when copying text from Publisher and pasting into another program when there is a narrow non-breaking space at the boundary of formatting. This is a little hard to explain, but my demo file and demo screencast will hopefully make it clear.
In the file, I have two brief lines of text that seem visually identical, but there is a very minor difference: in the top specimen only the words between the guillemets are italicized, while the bottom specimen has the words and the narrow non-breaking spaces in italics.
Try this: open the file, copy all the text (not the text box), and paste into another application like TextEdit. Result: the second specimen has an extra space after the first guillemet.
If I had to guess, I suspect that this is an issue when a multibyte character comes against the boundary of a formatting change. If so, other multibyte characters may have some unpredictable behaviors as well.
Here is a video demonstration of the issue in case the written explanation is unclear.
narrow non-breaking space with formatting.mp4
narrow non-breaking space with formatting.afpub