seen in 0.13.alpha.10:
@include transition(opacity 0.5s ease, visibility 0.5s);
should output:
transition: opacity 0.5s ease, visibility 0.5s;
instead it outputs:
transition: opacity 0.5s ease visibility 0.5s;
--> without the comma!
I omited the prefixed versions here but the problem is the same for those