Fcitx forcefully activates Japanese input mode when I enter text to Konsole and Yakuake

[phanect]

I use fcitx5 (with a Japanese IME mozc) on KDE neon.

Recently, when I type a character on Konsole and Yakuake, the input mode is forcefully changed to Japanese Hiragana regardless of the input mode I used on the other apps.
I can switch back to English by pressing the key to deactivate the input method (Hankaku/Zenkaku key), but I have to press the key every time I open Yakuake and Konsole.

I took a screencast to show the current behavior. I never pressed keys to activate/deactivate/toggle the input method while I was taking this screencast.

https://www.youtube.com/watch?v=2VJHQWLtlFE

First, I set the input mode to English. I pressed the "a" key on Kate, and "a" is displayed in Kate as expected.
Next, I switched to Konsole, then I pressed "a" again. I expected "a" to be displayed as well, but Japanese "あ" is displayed instead. This means that the Japanese input method is enabled on Konsole.
At last, I went back to Kate and pressed "a", then "a" was displayed. This may imply that the input method mode is separately managed on Konsole.

I tried Electron apps (GitHub Desktop Linux) and GTK apps (Meld) instead of Kate, but the results were the same.

When I tried Google Chrome's address bar, the result was the same, but interestingly, when I tried with a text field in a website on Google Chrome, the behavior was a bit different:

1. Enter "a" on a website's text field on Google Chrome, then "a" is displayed.
2. Switch to Konsole and enter "a" again, then "a" is displayed. (expected)
3. Switch from Konsole to Yakuake and enter "a" again, then Japanese "あ" is displayed. (unexpected)

I'm not sure if this is a bug of fcitx5 or other software including Konsole, Yakuake, and Plasma, so I need help to find the cause.

This issue started to happen several weeks or months ago. It might have started after the Plasma 6.2 upgrade, but I might remember incorrectly. Sorry.

I have asked the same question on KDE Discuss, but couldn't find the cause and solution:

Fcitx forcefully activates Japanese input mode when I enter text to Konsole and Yakuake | KDE Discuss

My env:

• The OS/Distro I tested: KDE neon (all updates applied as of 2025/02/15 2:10 AM UTC)
• fcitx 5.1.7
• Plasma 6.3.0 with Wayland
• Konsole/Yakuake 24.12.2

Thanks in advance.