multifile output not creating yaml stream

I have a jsonnet which outputs a json of the form `{out.yaml: [{a:1},{b:2}]}` (json simplified for this example).

When I run the command `jsonnet -y -m.` I do not get the intended yaml stream in the out.yaml file. Instead I get the json format output `[{a:1},{b:2}]}`.

Is this expected behavior?
I also ran the same command but using jrsonnet (`jrsonnet -y -m.`) and I obtain the yaml stream as I would expect