Upstream commits:

commit 3ce626c4a8c530aa08d05534a799a742a940e21a
Author: Abhishek Gupta <abhgupta@redhat.com>
Date:   Wed May 28 14:48:10 2014 -0700

    Bug 1067404: Handling additional storage correctly at the group level

commit 7102c9c830a4f7da6295ccd11e2e8f53f6993f70
Author: Abhishek Gupta <abhgupta@redhat.com>
Date:   Mon Jun 16 11:59:11 2014 -0700

    Bug 1109646: dup was being called on nil

Check on puddle[2.1.5/2014-08-01.1]

1.create a scalable app
#rhc app create phps php-5.4 -s
2.add storage
rhc cartridge storage -c haproxy-1.4 -a phps --add 4gb 
3.show the storage
rhc cartridge storage -c haproxy-1.4 -a phps --show  
RESULT:
Web Load Balancer
-----------------
  Base Gear Storage:       1GB
  Additional Gear Storage: 4GB
4. remove storage twice
rhc cartridge storage -c haproxy-1.4 -a phps --remove 1
5.check the storage 
#rhc cartridge storage  -a phps
RESULT:

Web Load Balancer
-----------------
  Base Gear Storage:       1GB
  Additional Gear Storage: 2GB
6.login the app and run 'quota -s'
>quota -s
Disk quotas for user 53df203316ae31a3ce000065 (uid 5656): 
     Filesystem  blocks   quota   limit   grace   files   quota   limit   grace
/dev/mapper/vg_rhel65-lv_root
                   1092       0   3072M             237       0    240k

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.

http://rhn.redhat.com/errata/RHBA-2014-1095.html