Unrounded unit values don't seem to be supported

[mdings]

trafficstars

I'm trying to use foundation's rem-calc function which can potentially output values like 21.875rem. Element queries containing unrounded unit values seem to be getting ignored completely:

.program {
  background: red;
    &[min-width~="#{rem-calc(350)}"] { //outputs 21.875rem
      background: blue; //background still red
    }
 }

.program {
  background: red;
    &[min-width~="#{rem-calc(336)}"] { //outputs 21rem
      background: blue; //background blue
    }
 }

[marcj]

What kind of css does this produce exactly?