I know this has been mentioned several times that the skirt doesn't always match the first layer.
I wanted to point out that it's worse than that though. It doesn't always match the object at all.. In this case, a standard 20mm cube offset slightly to not be on the platform then print with support. The skirt changes shape from square to triangle.
Anyway, I tried on a couple objects to print a brim of several layers when I was experimenting with a small corner and sticking to the hot bed but I was unable because I couldn't get the brim to match the part. Hopefully a bug that can be squashed soon.