I found a character encoding issue when displaying the Patrons "circ notes" inside the Patron list.
Replicate like this:
1. Tools -> Patron lists -> Add patrons
2. Add a patron with diacritics and crazy stuff in their "circ notes"-field.
LIKE "Circnotesäålöäåöäåsöäååaädöfäaåöfåwe \\þ$ @\r \fĸjw@ }tĸ}\Q£ \RQWAF "
3. Observe mayhem
*** This bug has been marked as a duplicate of bug 11906 ***