Multiline fields echo -smq issue

[marcde...@gmail.com]

I want to change the CSV delimiter from comma
to semicolon.
It seems there is a bug with echo -smq -osep ;
if the input file contains multiline fields:
The output doesn't quote these multline fields.

multiline.csv:
batman,"the caped crusader,
scourge of the underworld"
thor,"mighty,
hammer swinging god"

csvfix echo -smq -osep ; multiline.csv
=>
batman;the caped crusader,
scourge of the underworld
thor;mighty,
hammer swinging god

Am I doing something wrong or is this a bug?

This would be the correct expected output:
batman;"the caped crusader,
scourge of the underworld"
thor;"mighty,
hammer swinging god"