Hi Christof:

I did two different fixes for this. I replaced rev 918792e35e0 with
rev 166cb26323 which changes the line you deleted to:

    represent[col] = repr_list(cclass, 'id')

It now produces: "1;3" for the normal (named/labeled) export csv and "['1', '3']"
for the id version of export csv.

If the class has a name field the names of the items are printed rather than the
ids.

Thanks for finding this and submitting a fix change and a reproducible test case.
It made my work a lot easier.

Happy holidays.

-- rouilj