su-exec sets $HOME, and we used to have this env call in there to fix that up. It disappeared in the latest entrypoint.sh rewrite.
@@ -4,4 +4,4 @@ set -eu
chown "${PUID}:${PGID}" "${HOME}" \
&& exec su-exec "${PUID}:${PGID}" \
- "$@"
+ env HOME="$HOME" "$@"