"lpoptions -W completed -o" does not work over domain sockets on RHEL-5.5 with CUPS 1.3.7

[pipitas]

RHEL-5.5 with CUPS v.1.3.7.

In my cupsd.conf I have this setting:

   Listen *:50784
   Listen /var/run/cups/cups.sock

Now I would assume the following two commands to give the very same result:

   lpstat -h localhost:50784 -W completed -o
   CUPS_SERVER=/var/run/cups/cups.sock lpstat -W completed -o

However, the second command does not return any info about completed 
jobs (the first one does -- it shows 14 jobs having completed so far).

Other lpstat command variations work:

   lpstat -h localhost:50784 -p
   CUPS_SERVER=/var/run/cups/cups.sock lpstat -p

list all printers. Other commands also work; listing devices:

   lpinfo -h localhost:50784 -v
   CUPS_SERVER=/var/run/cups/cups.sock lpstat -v

listing PPDs/models:

   lpinfo -h localhost:50784 -m
   CUPS_SERVER=/var/run/cups/cups.sock lpstat -m

listing printer options:

   lpoptions -h localhost:50784 -l -p myprinter
   CUPS_SERVER=/var/run/cups/cups.sock lpoptions -l -p myprinter

So my questions are:

  * Is/was this a known bug in CUPS v.1.3.7?
  * Is/was this a known bug in RHEL's patches to vanilla CUPS-1.3.7?