linux command same position show difference thing

Question

I use command ls in the same position, but show diff things.

[tiankonguse /usr/local/services/video_sphinx-1.0]# pwd;ls -a;ls -a ../video_sphinx-1.0/
/usr/local/services/video_sphinx-1.0
.  ..  bin  conf  etc  var
.  ..  conf  etc  incSphinxIndex.sh  indexer  search  searchd  syncCoverToSphinx.py

[tiankonguse /usr/local/services/video_sphinx-1.0]# cd ../video_sphinx-1.0/
[tiankonguse /usr/local/services/video_sphinx-1.0]# pwd;ls -a;ls -a ../video_sphinx-1.0/
/usr/local/services/video_sphinx-1.0
.  ..  bin  conf  etc  var
.  ..  conf  etc  incSphinxIndex.sh  indexer  search  searchd  syncCoverToSphinx.py