Data Importer failed due to name of the backup file

During an upgrade, when applying a backup to a fresh install of Domino 5.1 via the data importer (with postgres data), it failed with below error message, 

Running postgres migration...
Backing up local postgres db to /opt/scratch/postgres/postgres_archive_local-backup_20220413-233813.gz...
Running: ['pg_dump', '-h', 'postgresql', '-U', 'postgres', '-Z', '9', 'keycloak'], piping to /opt/scratch/dev-postgres.sql
Dropping and recreating 'keycloak' database...
Sending UPDATE pg_database SET datallowconn = 'false' WHERE datname = 'keycloak' to postgres...
UPDATE 1

Sending SELECT pg_terminate_backend(pid) FROM pg_stat_activity WHERE datname = 'keycloak' to postgres...
pg_terminate_backend
---------------------- t
(1 row)

Sending DROP DATABASE keycloak to postgres...
DROP DATABASE

Sending CREATE DATABASE keycloak to postgres...
CREATE DATABASE

Restoring postgres from /opt/scratch/dev-postgres.sql...
Sending file data to postgres...

Traceback (most recent call last):
File "src/importer/importer", line 275, in <module>
main()
File "src/importer/importer", line 40, in main
Importer().process_all()
File "src/importer/importer", line 269, in process_all
[q.migrate() for q in queue]
File "src/importer/importer", line 269, in <listcomp>
[q.migrate() for q in queue]
File "/app/src/importer/import_workers/postgres.py", line 96, in migrate
self.psql_cmds(stdin=f, db="keycloak", encoding=None)
File "/app/src/importer/import_workers/postgres.py", line 143, in psql_cmds
raise WorkerException(f"Command [{psql_cmd}] exited with {p.returncode}: {p.stderr}")
importer.import_workers.WorkerException: Command [['psql', '-h', 'postgresql', '-U', 'postgres', '-d', 'keycloak']] exited with 0: b'invalid command \\@\xc2\x198\xb4\ninvalid command