About 10 minutes after boot, ibus-daemon takes 100% cpu usage and stays there
forever. Burning up my battery life and slowing down the system.
If I manually kill it then the problem immediately goes away. Even if I close
down Anthy / IME after login the problem still happens.

For the input methods configured in ibus-setup, I have "English - English (US)"
and "Japanese - Anthy"

Was not having this issue on Debian oldstable / buster.

Currently using LXDE / Openbox.

Not really sure how to troubleshoot a 100% CPU usage ibus-daemon problem.

Hello David,

This issue might be very hard for the maintainer to diagnose
if he cannot reproduce it.

As a starting point you probably could collect the output of
following command after the spike was visible for a few minutes.
This should give one line with a few minutes in the "TIME" column.

     ps -eLf | grep -i -E "PPID|ibus-daemon"

And additionally after installing gdb and giving this command, which
attaches a debugger to the daemon and printing a backtrace for each thread.

     gdb -q --pid $(pidof ibus-daemon) -ex 'set width 0' -ex 'set pagination off' -ex 'thread apply all bt' -ex 'detach' -ex 'quit'

Those two outputs might point to the thread inside ibus-daemon and
in which function it is currently executing.

Kind regards,
Bernhard