[Kitty preview terminal] German ß/? key inserts every character twice

What version of Codex CLI is running?

codex-cli 0.149.0

What subscription do you have?

api key (credits)

Which model were you using?

gpt-5.6-sol

What platform is your computer?

Microsoft Windows NT 10.0.26200.0 x64

What terminal emulator and version are you using (if applicable)?

WSL Windows Preview Terminal 1.25.1912.0

Codex doctor report

What issue are you seeing?

After switching Codex to the Kitty preview terminal, the physical German ß/? key is processed twice.

• Pressing ß once inserts ßß.
• Pressing Shift+ß once inserts ??.
• Other keys appear to work normally.
• Switching back to the stable/non-Kitty terminal fixes the problem.

What steps can reproduce the bug?

1. Enable the Kitty preview terminal in Codex.
2. Select the German QWERTZ keyboard layout.
3. Open codex cli
4. Press the ß key once.
5. Observe that ßß is inserted.
6. Hold Shift and press the same key once.
7. Observe that ?? is inserted.

What is the expected behavior?

Each key press should insert exactly one character: ß or ?.

Additional information

_No response_