I have this problem on two computers now. I had the Japanese language pack installed, and used the IME keyboard. I used to be able to use CTRL-CAPSLOCK to switch to Hiragana after changing the language to Japanese. I could also right click the A icon in the system tray and pick Hiragana from the menu. This allowed me to type romaji which were changes to the appropriate hirgana/kanji. But after installing the April 2018 update 1803, both methods don't change from half-width alpha-numeric.
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