(I upgraded from OOO320m18 (I think) to the current OOO330m20 (Build: 9567) to 
check if the issue was gone--it is in the current version too.)

I wanted to compare lists (modules in two httpd.conf files) using spreadsheet
text functions to find differences in the lists. 

Entering this compound boolean function trying to find and match strings, but 
having mismatched string delimiters, results in OO Calc auto-correcting it with 
an unmatched parenthesis at the end.  

I typed/copied into a cell (e.g. F75, but it works on row 3 too.):  

=IF (AND(IF(FIND("#";A75)=1);IF(D75=B75));"add";'keep"  )

...Delimiters for 'keep" are mismatched


Calc immediately adjusts this--without indicating an error--to:

=IF (AND(IF(FIND("#";A75)=1);IF(D75=B75));"add";'keep"  ))
....1...2..3....4.......4..3...3.......32...............1X

Delete the extra right parenthesis, hit enter, and it is still there.

Saving the file (.xls format), closing OO, and reopening the spreadsheet shows
the formula further corrected (properly, I presume) to

=IF(AND(IF(FIND("#";A75)=1;TRUE());IF(D75=B75;TRUE()));"add";"keep")
...1...2..3....4.......4.......443...3............4432.............1


The data in the cells A75:E75 are
A75: #LoadModule userdir_module modules/mod_userdir.so
B75: =MID(A75;FIND(" ";A75;1);10)
C75: LoadModule userdir_module modules/mod_userdir.so
D75: =MID(C75;FIND(" ";C75;1);10)
E75: =IF(D75=B75;".";"x")
F75:  the bug-evoking formula above