Chinese IME candidate window appears when pressing/holding keys in-game

In Minecraft Java Edition 26.3, when a Chinese IME is active, pressing or holding any keyboard key while in-game opens the IME composition/candidate window. For example, holding W displays an IME candidate list similar to:

1 呜呜呜呜呜呜呜呜
2 问问我www

This interferes with movement and other gameplay controls. Pressing Caps Lock and then Space temporarily fixes the issue.

This is a regression from 26.2. In 26.2, even when a Chinese IME was active, Minecraft appeared to switch to English/raw input while the game window was focused, so holding W did not open the IME candidate window. In 26.3, this no longer happens.