As soon as I can see, the hunspell team haven't fixed the bug in more 
then 2 years. Maybe for them it is not a bug but a feature.

The problem is that hunspell reports byte-position instead of 
char-position with multi-byte character input, while Emacs waits for 
char-position. With the patch attached I propose to make conversation in 
the ispell-parse-output function.

Thanks,
Nikolay Suschenko