If a file with an accent (e.g. "é") is part of a list of changes, the changelog.xml file will be apparently unreadable. For example, the character "é" ends up as 0xE9 in the xml file. Jenkins then shows No changes. in the build information. By manually editing changelog.xml and replacing 0xE9 by "é", a simple refresh of the page shows the proper changes.
Note that accents in changeset comments are handled correctly.
I set the priority to "Major" because one of the consequences of this is that no e-mails are sent because it thinks there are no changes, therefore nobody made changes.
The job console output shows: An attempt to send an e-mail to empty list of recipients, ignored.
This can mean a build failure without notification (which was our case). Whether this is a minor or major loss of function depends on the usage, I guess.