Error: quota-status: Client sent invalid recipient address: Invalid character in path

[Lefteris Tsintjelis via dovecot]

Any idea what this is?

Jun 26 23:16:34
quota-status(u...@example.com)<4975><CLsXEzfSE11vEwAArt9ycg>: Error:
quota-status: Client sent invalid recipient address: Invalid character
in path

I have this enabled in my config

service quota-status {
  client_limit = 1
  executable = quota-status -p postfix
  unix_listener /var/spool/postfix/private/dovquota {
    mode = 0666
    user = postfix
  }
}

Lefteris