just for the record: VLOOKUP IS NOT BROKEN BUT YOUR SOURCE-DATA (edit by karolus)
I use multiple VLOOKUP functions to select and to consolidate data. The Workbook was created in LO version 4.0.4.2 for Windows and was working fine on a Windows 7 laptop. Then I copied the Book to a desktop computer running Windows 7 with a fresh install of LO 4.4.1.2 and opened the file. Many of the VLOOKUP functions no longer worked correctly. When searching a Table where the index field is sorted but has duplicates some lookups worked correctly, some returned the result from the LAST row containing that index value and some returned N/A. Changing the index value on the destination page from numerical 1,2,3,4 etc to text 1,2,3,4 etc fixed some and broke others. Then I found the results of the VLOOKUP changed from the first row with a particular index value to the last row with that index value when I included the VLOOKUP inside an IF statement.