custom reason works for bucket listing, but it doesn't work object listing.

$ cat ~/.aws/credentials 
[default]
aws_access_key_id = AKIA991Z6427QRER7O91
aws_secret_access_key = HBwlovGPG2u9bVAcytO+a97GI4m3K7JT1RkrvzNh
region = jp

$ ./s5cmd version 
v1.4.0-rc.1-a0791f8

$ ./s5cmd --endpoint-url http://s3ds-1 ls 
2021/09/20 01:08:01  s3://bucket1

$ ./s5cmd --endpoint-url http://s3ds-1 ls s3://bucket1
ERROR "ls s3://bucket1": AuthorizationHeaderMalformed: The authorization header is malformed; the region 'us-east-1' is wrong; expecting 'jp' status code: 400, request id: 611C446F010F3B13, host id: 611E5582312F22A8