It doesn't look like it's going to be fixed soon.
It might be a good idea to not ship channels-redis 4.0.0 in bookworm.
I ran into this too just now, and it was very confusing. I was able to
work around it by switching to RedisPubSubChannelLayer, but I'm not
totally sure that's a good idea: it's still marked as being in beta even
now, 4.0.0's RedisPubSubChannelLayer also suffers from https://github.com/django/channels_redis/issues/343, and in my
application the switch provoked some kind of extremely weird coverage
failure, possibly https://github.com/python/cpython/issues/106749.