This seems to be fixed with BZ (https://bugzilla.redhat.com/show_bug.cgi?id=1044980) and Errata (http://rhn.redhat.com/errata/RHBA-2014-0781.html) for 1.8, but not 1.9.

The issue in ruby 1.8 was a confusing error message but no functionality was technically broken.  Is this the same case or is functionality broken in some way?

Could reproduce with ruby193-rubygem-passenger-3.0.21-3.el6op.x86_64.
This should be the same issue with ruby 1.8. 
Hardcode '127.0.0.1' could be seen in /opt/rh/ruby193/root/usr/share/gems/gems/passenger-3.0.21/helper-scripts/prespawn

 99 class TCPPrespawnLocation < PrespawnLocation
100         def request_port
101                 @uri.port
102         end
103 
104         def connect
105                 TCPSocket.new('127.0.0.1', request_port)
106         end
107 end

(In reply to Brenton Leanhardt from comment #4)
> The issue in ruby 1.8 was a confusing error message but no functionality was
> technically broken.  Is this the same case or is functionality broken in
> some way?

Customer confirmed that this is not something that breaks the application, but is a reporting issue.

Verify this bug with ruby193-rubygem-passenger-3.0.21-4.el6op.x86_64

The hardcode has been removed. 
No error found in ruby-1.8/ruby-1.9 application log.

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://rhn.redhat.com/errata/RHBA-2015-1463.html