Error on writing 2D table from set of pairs #9

The example transp3.mod + transp3.dat from the AMPL book has the following definitions:

set ORIG;
set DEST;

set LINKS within {ORIG,DEST};
var Trans {LINKS} >= 0;

The data for LINKS is a subset of the origin-destination pairs. A 2D spreadsheet table of the Trans variables can be specified equivalently as

table Transp3 OUT "amplxl" "2D" "Transp3.xlsx": {(i,j) in LINKS} -> [ORIG,DEST], Trans[i,j];

or

table Transp3 OUT "amplxl" "2D" "Transp3.xlsx": [ORIG,DEST], Trans;

But write table Transp3; fails with this error:

	Error writing table Transp3 with table handler amplxl:
	Could not write 2D data

When "2D" is removed from either table statement, the corresponding 1D table is written correctly.