```
$ guix package -I | grep ibus-anthy
ibus-anthy          	1.5.14              	out       	/gnu/store/93fbwxycshdz4gcqphcns3dk0x5fxayx-ibus-anthy-1.5.14
```

If I have a different condition than yours, it is that I was using
ibus-anthy, which I maintain on a private channel, so I did not update
from an older version to a newer version.

I just removed ibus-anthy from my private channel as it was recently
fixed by upstream[0].

I would like to help you solve your problem.

I'm not very familiar with IBus or ibus-anthy either, so if you have any
settings or command execution results you would like to compare with my
environment, please let me know.

[0]: https://git.sr.ht/~taiju/taix/commit/d834c66

Best Regards,
-- 
Taiju