The issue with CJK input methods has not been fully resolved in the latest preview version.
Currently, if you directly enter a world after launching the game, keyboard input may still incorrectly trigger the input method. For input to function correctly with CJK input methods enabled, you must first click on a text field with the mouse to give it focus before starting to type.
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We're tracking this issue at MCPE-230162, so this ticket is being resolved and linked as a duplicate.
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