Interesting…
The desired character “ä” is Unicode U+00E4 / UTF-8 C3 A4.
The substituted characters “Ô and “¤” are, respectively, Unicode U+00C3 / UTF-8 C3 83
and Unicode U+00A4 / UTF-8 C2 A4.
It seems that it took the desired character’s UTF-8 value of C3 A4 and created the two characters 00 C3 and 00 A4.