Is this a bug? Any help would be great

Hi Guys,

I am trying to list some womens leggings but the sizing info will not update. Is this a bug?

I have attached an image.

bug.jpg 1043×701 82.4 KB

The leggings are size 12 - womens - uk.

You can see i am selecting numeric but it will not update and even when i select sizing system uk - it says error?

What am i missing?

Thanks for your help guys,