Created attachment 85435 [details]
Excel file used in the report

I have produced an Excel spreadsheet with a validity check for cells. It concerns column A. 
Cell A1 is the column header.
Cell A2 has validity check by formula: =COUNTIF(A$1:A1;A2)=0. According to Excel, only values inserted in A2 which amke this formula produce TRUE are permitted. 

Cells A2:A10 are copied down from A1, so that each cell contains a check with a formula counting the present value among all cells above itself.
Effectively, in Excel cells A2:A10 have a validity check that requires that the value in a cell is not a duplicate of a value above it. Entering a duplicate produces a warning message and is rejected, as expected.

LibreOffice does not permit validity check by formula. However, if I download the file into LibreOffice, the formula from the Excel file somehow gets into the validity check and causes it to operate in a way difficult to explain. 

First of all, "Validity" reports "Allow all values", but there is a (grayed out) restriction to a valid range, with the formula from Excel shown as the minimum value, 0 being the maximum.

Next, entry of values into the affected cells is restrcted in a very unpredictable way. 
- one can enter 0 values one by one, starting from top.
- one can enter 1 values one by one, starting from top.
- if one enters a few 0 values, and then a single 1, this input is rejected.
- if one enters a few 1 values, and then a single 0, this input is permitted.
- Entering 2 and string "a" is always rejected, not matter where and if there are other value sin the cells A2:A10 or not.