String interpolation, list and !important keyword

I noticed something odd about string interpolation and lists:

.test-list {
  content: "@{variable}" !important;
  @variable: This is !important;
}

compiles into:

.test-list {
  content: "This is" !important;
}

I would expect it to be:

.test-list {
  content: "This is !important" !important;
}

I think it is just a minor issue, because following works correctly:

.test-string {
  content: "@{variable}" !important;
  @variable: "This is !important";
}

Reproduce the two interpolation examples from the issue and compare the compiled output with the expected CSS. The work is done when a list-valued variable preserves “!important” inside the interpolated string while the declaration’s own “!important” remains intact, without changing the existing quoted-string behavior.