Korean IME: first consonant duplicated after Shift+Enter newline

[ndaemy]

Description

When typing Korean (Hangul) in the desktop app's prompt input, pressing Shift+Enter to insert a newline and continuing Korean input causes the first consonant to be duplicated.

Specifically: the initial consonant (자음) appears fine, but when the following vowel (모음) is typed to form a syllable, the consonant is duplicated after the cursor. For example, typing 한 after Shift+Enter:

Type ㅎ → displays ㅎ (correct)
Type ㅏ → displays 하ㅎ with cursor at 하|ㅎ (incorrect — expected 하)
It is very intermittent and cannot be reproduced.

Note: #8275 addressed a Shift+Enter IME stuck state, but still occurs on v1.2.8.

Plugins

No response

OpenCode version

1.2.8

Steps to reproduce

1. Switch to Korean (한글) input method
2. Type any text
3. Press Shift+Enter to insert a newline
4. Type a Korean consonant (e.g. ㅎ) — displays correctly
5. Type the following vowel (e.g. ㅏ) — the consonant is duplicated after the cursor: 하ㅎ instead of 하

Screenshot and/or share link

bug-1.mov

Operating System

macOS 26.3

Terminal

No response