Why "-T" can not output 'stl' file in 2D by "-format" ?

[hubocqjtu]

Dear all,
Why the neper can not output the "stl" file?
Code:
$ neper -T -n 1000 -id 1 -morpho "voronoi,aspratio(1.5,0.5)" -transform "rotate(0,0,1,45)" -domain "square(5,5):rotate(0,0,1,-45)" -dim 2 -format "stl"
Result:

[rquey]

This is fixed in version 4.1.2-12.