This one is a spin off of "Bug 51524 - [Fileopen] [XLS] cell-width of invisible cells are not remembered", where this problem has been reported additionally to an other problem.

Because it's not clear how sample document of Bug 51524 has been created you also can use Attachment 70503 [details] of Bug 57477, what has been created as Excel8 document with Excel 2010, and create your own .xls from LibO following steps 1-4 of Bug 57477.

[Reproducible] with "LibreOffice Portable 3.3.0  - WIN7  Home Premium (64bit) German UI [OOO330m19 (Build:6) tag libreoffice-3.3.0.4]":

0. download Attachment 63569 [details] of a.m. Bug, what seems to 
1. Open sample document from LibO start center
   Expected: above column Heading 'D' you should see a small '+' button
             to expand the 2 hidden columns
   Actual: you see a small '-' button to collapse columns, but they are already
           collapsed
2. Click '-'
   As expected, nothing happens with columns, columns are already collapsed.
   But button changes to '+', Clicking it will expand the 3 columns, 
   clicking the now visible '-' will hide columns a-C and so on

So it looks as if there simply would be a FILEOPEN - UI problem, but I did an additional test, what might be interesting for deeper understanding of this bug, but are not necessary 

11. Open a.m. Sample document with MS Excel 2010
    > A correct '+' button will be shown above 
12. Expand Columns A-C and collapse again
13. Save as "document2010.xls", exit
14. Redo step 1
    As expected: above column Heading 'D' you see a small '+' button
                 to expand the 3 hidden columns
   
So there might be a LibO Filesave problem? I submitted a separate "Bug 57477 - FILESAVE as .xls with wrong info concerning collapsed grouped columns" for that.

NEW due to results on <discuss@de.libreoffice.org>
 <http://listarchives.libreoffice.org/de/discuss/msg12890.html>

Same problem with OOo 3.1.1, so inherited from OOo.

Still  [Reproducible] with parallel installation of  "LOdev  4.0.0.0.alpha0+   -  ENGLISH UI / German Locale  [Build ID: a2b3ee)]"  {2012-11-22} on German WIN7 Home Premium (64bit) with separate /4 User Profile for 4.0

@Spreadsheet Team
Please set Status to ASSIGNED and add yourself to "Assigned To" if you accept this Bug or forward the Bug if it's not your turf (and remove others in team from CC).