Created attachment 120252 [details]
The attachement containes the replication of the bug
Using the matrix formula as in attached example it seems that LibreOffice does not honour the "Range include header columns". It worked on previous versions (4.3).
Started in 18.104.22.168, so I add Eike to CC. I don't know if that's related to Bug 42481 but doesn't seem fixed in Bug 91453.
The sample attempts to calculate with text strings in an array, which by chance worked under some circumstances when all text was expected to be treated as zero. This IS fixed with bug 91453, but you have to specify in Tools->Options->Calc->Formula "Detailed Calculation Settings" * Custom -> Details "Contents to Numbers" "Conversion from text to number" "Treat as zero".
Above all, calculating with text should be avoided.
*** This bug has been marked as a duplicate of bug 91453 ***