This issue occurs when you use JustSystems's ATOK as your input method editor (IME) and set Romaji input mode as the default. Japanese Kana input mode is enabled accidentally when you focus on an input field with the IME in active mode in Internet Explorer 11.
For example, when the IME is in active mode, and you enter the letters k and a in an input field, Internet Explorer incorrectly enters two Japanese hiragana syllables no and ti (“のち”) instead of the expected single Japanese syllable ka ("か").
To fix this issue, install the most recent cumulative security update for Internet Explorer. To do this, go to Microsoft Update. Additionally, see the technical information about the most recent cumulative security update for Internet Explorer.
Note This update was first included in the MS16-009: Security update for Internet Explorer: February 9, 2016.
Microsoft has confirmed that this's a problem in the Microsoft products that are listed in the "Applies to" section.
Learn about the terminology that Microsoft uses to describe software updates.
The third-party products that this article discusses are manufactured by companies that are independent of Microsoft. Microsoft makes no warranty, implied or otherwise, about the performance or reliability of these products.