The ISOLatin1AccentFilter is removing accents from accented characters in the ISO Latin 1 character set.
It does what it does and there is no bug with it.
It would be nicer, though, if there was a more comprehensive version of this code that included not just ISO-Latin-1 (ISO-8859-1) but the entire Latin 1 and Latin Extended A unicode blocks.
That way, all languages using roman characters are covered.
A new class, ISOLatinAccentFilter is attached. It is intended to supercede ISOLatin1AccentFilter which should get deprecated.