https://bugs.winehq.org/show_bug.cgi?id=45982
--- Comment #1 from Sagawa sagawa.aki+winebugs@gmail.com --- I can reproduce this issue. Now, I'm preparing a patch with test cases.
There is a bug inside required buffer size calculation. Unfortunately, it's unconsidered that both LCMAP_KATAKANA and LCMAP_HALFWIDTH are used. Voiced sound Hiragana characters (e.g. が) and semi-voiced sound Hiragana characters (e.g. ぱ) are affected.