PXB is unable to connect to the database with transition-key when password is specified

/home/mchawla/PS230719_8_0_16_6_debug/bin/mysqld --no-defaults --core-file --basedir=/home/mchawla/PS230719_8_0_16_6_debug --tmpdir=/home/mchawla/PS230719_8_0_16_6_debug/data --datadir=/home/mchawla/PS230719_8_0_16_6_debug/data --plugin-load-add=tokudb=ha_tokudb.so --tokudb-check-jemalloc=0 --plugin-load-add=rocksdb=ha_rocksdb.so --socket=/home/mchawla/PS230719_8_0_16_6_debug/socket.sock --port=12915 --log-error=/home/mchawla/PS230719_8_0_16_6_debug/log/master.err --server-id=100 --early-plugin-load=keyring_file.so --keyring_file_data=/home/mchawla/PS230719_8_0_16_6_debug/keyring --binlog-encryption --innodb-undo-log-encrypt --default-table-encryption=ON --innodb_encrypt_online_alter_logs=ON --innodb_temp_tablespace_encrypt=ON --log-bin=mysql-bin --log-slave-updates --gtid-mode=ON --enforce-gtid-consistency --binlog-format=row --master_verify_checksum=ON --binlog_checksum=CRC32 --encrypt-tmp-files --innodb_sys_tablespace_encrypt --innodb_parallel_dblwr_encrypt --binlog-rotate-encryption-master-key-at-startup --table-encryption-privilege-check=ON --innodb-default-encryption-key-id=4294967295 --innodb-encryption-threads=10

./xtrabackup --user=root --password='' --backup --target-dir=$HOME/dbbackup_PS8/full -S $HOME/PS230719_8_0_16_6_debug/socket.sock --datadir=$HOME/PS230719_8_0_16_6_debug/data --keyring_file_data=$HOME/PS230719_8_0_16_6_debug/keyring --xtrabackup-plugin-dir=$HOME/pxb_8_0_7_debug/lib/plugin --transition-key=abc
 xtrabackup: recognized server arguments: --datadir=/var/lib/mysql --datadir=/home/mchawla/PS230719_8_0_16_6_debug/data 
 xtrabackup: recognized client arguments: --user=root --password=* --backup=1 --target-dir=/home/mchawla/dbbackup_PS8/full --socket=/home/mchawla/PS230719_8_0_16_6_debug/socket.sock --xtrabackup-plugin-dir=/home/mchawla/pxb_8_0_7_debug/lib/plugin --transition-key=* 
 ./xtrabackup version 8.0.6 based on MySQL server 8.0.16 Linux (x86_64) (revision id: 8704f50)
 190730 13:44:24  version_check Connecting to MySQL server with DSN 'dbi:mysql:;mysql_read_default_group=xtrabackup;mysql_socket=/home/mchawla/PS230719_8_0_16_6_debug/socket.sock' as 'root'  (using password: YES).
 Failed to connect to MySQL server: DBI connect(';mysql_read_default_group=xtrabackup;mysql_socket=/home/mchawla/PS230719_8_0_16_6_debug/socket.sock','root',...) failed: Access denied for user 'root'@'localhost' (using password: YES) at - line 1535.
 190730 13:44:24 Connecting to MySQL server host: localhost, user: root, password: set, port: not set, socket: /home/mchawla/PS230719_8_0_16_6_debug/socket.sock
 Failed to connect to MySQL server: Access denied for user 'root'@'localhost' (using password: YES).

./xtrabackup --user=root --backup --target-dir=$HOME/dbbackup_PS8/full -S $HOME/PS230719_8_0_16_6_debug/socket.sock --datadir=$HOME/PS230719_8_0_16_6_debug/data --keyring_file_data=$HOME/PS230719_8_0_16_6_debug/keyring --xtrabackup-plugin-dir=$HOME/pxb_8_0_7_debug/lib/plugin --transition-key=abc
xtrabackup: recognized server arguments: --datadir=/var/lib/mysql --datadir=/home/mchawla/PS230719_8_0_16_6_debug/data 
xtrabackup: recognized client arguments: --user=root --backup=1 --target-dir=/home/mchawla/dbbackup_PS8/full --socket=/home/mchawla/PS230719_8_0_16_6_debug/socket.sock --xtrabackup-plugin-dir=/home/mchawla/pxb_8_0_7_debug/lib/plugin --transition-key=* 
./xtrabackup version 8.0.6 based on MySQL server 8.0.16 Linux (x86_64) (revision id: 8704f50)
190730 13:51:50 version_check Connecting to MySQL server with DSN 'dbi:mysql:;mysql_read_default_group=xtrabackup;mysql_socket=/home/mchawla/PS230719_8_0_16_6_debug/socket.sock' as 'root' (using password: NO).
190730 13:51:50 version_check Connected to MySQL server
190730 13:51:50 version_check Executing a version check against the server...
190730 13:51:50 version_check Done.
190730 13:51:50 Connecting to MySQL server host: localhost, user: root, password: not set, port: not set, socket: /home/mchawla/PS230719_8_0_16_6_debug/socket.sock
Using server version 8.0.16-6-debug
xtrabackup: uses posix_fadvise().
xtrabackup: cd to /home/mchawla/PS230719_8_0_16_6_debug/data
xtrabackup: open files limit requested 0, set to 1048576
xtrabackup: using the following InnoDB configuration:
xtrabackup: innodb_data_home_dir = .
xtrabackup: innodb_data_file_path = ibdata1:12M:autoextend
xtrabackup: innodb_log_group_home_dir = ./
xtrabackup: innodb_log_files_in_group = 2
xtrabackup: innodb_log_file_size = 50331648
...