Regular Expression fails to match

[Bruno]

It seems to be a BUG related to the regex engine:

Sample Line To Search (there are no tabs):
bli wh hummm e lzts txst 2 4

(There are multiple spaces between most words on the sample line above.
A file 'bug_sample_file' has been uploaded and it contains the line as it really is)

Searching consecutively from the start of the sample line above:
/\S\s\+\S

it doesn't stop on the char 'e' and on the char '2' as (I think) it should.
Others stops (matches) are OK.

Likewise, searching:
/\S\s\{2,}\S

It doesn't stop on the '2' as (I think) it should.

The behavior is the same running:
vim -u NONE bug_sample_file
Attached is the file bugreport.txt generated by VIM via:
:so $VIMRUNTIME/bugreport.vim

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: vim-gnome 2:7.4.052-1ubuntu3
ProcVersionSignature: Ubuntu 3.13.0-45.74-generic 3.13.11-ckt13
Uname: Linux 3.13.0-45-generic i686
ApportVersion: 2.14.1-0ubuntu3.6
Architecture: i386
CurrentDesktop: Unity
Date: Tue Feb 17 11:45:22 2015
ExecutablePath: /usr/bin/vim.gnome
InstallationDate: Installed on 2011-06-25 (1332 days ago)
InstallationMedia: Ubuntu 11.04 "Natty Narwhal" - Release i386 (20110427.1)
ProcEnviron:
 LANGUAGE=en_US
 PATH=(custom, user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: vim
UpgradeStatus: Upgraded to trusty on 2014-08-03 (198 days ago)

[Bruno (brunosvianna)]

The file 'bug_sample_file' contains the sentence (without any spaces squeezed) to test the regex matching issue.

[Bruno (brunosvianna)]

Actually, it's not a BUG.