version of openOffice : OOO310m11 (Build:9399).
A spreadsheet contains formulas in a column that refer to fields on the same
worksheet. The reference to these fields may or may not include the worksheet name.
If the worksheet name is not included in the cell reference, the sort works as
expected.
If the worksheet name is included in the cell reference, the sort gives
unexpected results.
In Excel, the formulas are completely mixed up. In Calc, the behaviour is also
unexpected, but there seems to be a bit more structure.

It is easy to reproduce :
Create a spreadsheet as follows :
1;2;A1*B1;Sheet1.A1*B1
2;4;A1*B1;Sheet1.A2*B2
3;6;A1*B1;Sheet1.A3*B3
4;8;A1*B1;Sheet1.A4*B4
5;10;A1*B1;Sheet1.A5*B5
Then do a sort descending on column C or D. The first 3 columns sort as
expected, the fourth column does not sort, but the references are changed.