[calc]mmult with transpose arg drops last row

I've a spreadsheet with 2 3x2 matridces side by side (A1:D3).
I want to mmult(A1:B3;transpose(C1:D3)); however,
the result has the last row truncated. IOW, the
resulting matrix is 2x3 instead of 3x3.

The spreadsheet also has the transpose stored separately
in cells A5:C12, and then the mmult done with this separately
stored transpose, and the result is a 3x3 matrix, as expected.

Here's the printout of formulas in csv notation:

1,4,7,10
2,5,8,11
3,6,9,12

[snip]
Filed a bug report:

https://bugs.freedesktop.org/show_bug.cgi?id=73756