tab key stops showing options if some given patterns have been typed

Type this:
  rsync -avz -include=".*" ./* /me
and then hit the tab key

Expected: it should autocomplete /me to /media/ or show available autocomplete options if any

Observed: tab key does nothing.

Testing it a little bit, it seems the tab key stops working when a pattern like ="anything" has been typed.

For example, after typing:
 foo -bar="xyz"
the tab key stops working

However, after for example.
 foo -bar=""
it still works.

This doesn't make any sense.

ProblemType: Bug
DistroRelease: Ubuntu 13.04
Package: bash 4.2-5ubuntu3
ProcVersionSignature: Ubuntu 3.8.0-31.46-generic 3.8.13.8
Uname: Linux 3.8.0-31-generic i686
NonfreeKernelModules: nvidia
ApportVersion: 2.9.2-0ubuntu8.4
Architecture: i386
Date: Fri Oct 11 23:07:32 2013
InstallationDate: Installed on 2010-06-23 (1206 days ago)
InstallationMedia: Ubuntu 10.04 LTS "Lucid Lynx" - Release i386 (20100429)
MarkForUpload: True
ProcEnviron:
 TERM=xterm
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: bash
UpgradeStatus: Upgraded to raring on 2013-08-10 (62 days ago)