Unstable radial-gradient

[bo-ku-ra]

ignored
https://play.d2lang.com/?script=StS1S7JKy89PSiyqLi6pzEnVS8vPK9FNzs_JL7JSKEpNsVaACBeXFOVnp6IIpWXm5FgpJOUkJmfX8nIl69qlUGaSUlFiSmZijm46iE7NK9FQTgMDHQVlAzDQVKrl5QIEAAD__w%3D%3D&

a->b:foobar{style.font-color: red; style.stroke: red; style.fill: black}
c->d:foobar{style.font-color: red; style.stroke: red; style.fill: "radial-gradient(#ffffff, #000000)"}

expected
https://play.d2lang.com/?script=StS1S7JKy89PSiyqLi6pzEnVS8vPK9FNzs_JL7JSKEpNsVaACBeXFOVnp6IIpWXm5FgpJOUkJmfXciXr2qVQZpBSUWJKZmKObjqITs0r0VBOAwMdBWUDMNBUquVKpqXhgAAAAP__&

a->b:foobar{style.font-color: red; style.stroke: red; style.fill: black}
c->d:foobar{style.font-color: red; style.stroke: red; style.fill: "radial-gradient(#ffffff, #000000)"}
c{style.font-color: red; style.stroke: red; style.fill: "radial-gradient(#ffffff, #000000)"}