Edge Browser: fd-col--8 fd-col--4 not working

[fopsdev]

hi there

thanks for this wonderful css lib.
just stumbled over a nasty thing related to edge browser and the grid functionality.
a grid with fd-col--8 and fd-col--4 works fine in chrome and ff but not in edge.

check out (using edge browser) the index.html over at:
https://codesandbox.io/s/falling-wood-3tsyj?fontsize=14

i'm using edge 42.17134.1.0

thanks for any enlightment