memory leak when changing input method

[martinetd]

Please fill in the following items if you don't know the root cause.

Which distribution and version?:
debian bookworm

Which desktop environment and version?:
custom DE on X11 (wmii)

Which session type?:
X11

Which application and version?:
unrelated

IBus version?:
1.5.27-5

ibus-anthy version?:
1.5.14-1

Issue description:
ibus-anthy RSS grows by about 400KB everytime ibus-anthy is selected.
I see ibus anthy's engine/factory.py do_create_engine is called everytime so I assume the old factory sitll has references somewhere and is not gc'd?

Steps to reproduce:

1. in ibus-setup have at least two input methods (I have English - English and Japanese - Anthy) with a keyboard shortcot to select next input method
2. check RSS amount through e.g. ps aux | grep ibus-anthy
3. toggle input method
4. notice RSS grew
5. with a 3 months uptime my ibus-anthy has filled in over 5.5GB of RSS+swap

Can you reproduce your problem when you restart ibus-daemon? (yes / no):
yes

Do you see any errors when you run ibus-daemon with the verbose option?:
no error, messages about some cleanup happening:

Removing imported_words_ibus__oldchar
Removing imported_words_ibus__era
Removing imported_words_ibus__zipcode
Removing ibus__symbol
Removing imported_words_ibus__emoji

Can you reproduce your problem with a new user account instead of the current your account? (yes / no):
... I was sure it would reproduce but I actually can't! I tried copying my .bashrc/.Xdefaults, .anthy directory, .xsession file, dconf dump of /desktop/ibus and /org/freedesktop/ibus/... I don't see what else could impact this?
I can reproduce this on two PCs so it's not 100% random, but if I can't reproduce on another account I'm not sure you'll be able to, do you have any idea what could cause this kind of things? I see new engines being created too but the old ones are properly gc'd, so perhaps a bad client?... I've tried running the same programs I think I have right now but might have missed some..

Anyway, enough time spent on this for a short while, any idea to trim this down further would be appreciated.