Thanks Paul, that fixed the issue! Do you know why this was causing such a problem?
I’m guessing it’s because the two halves were appearing split with the border-radius of the mask set to 50%?
I think it’s just a bug with the animations. I’ve run into problems before with animations and border radius on safari and IOS so was the first place I looked.
Ah good to know - I had a feeling it something to do with the “clip” property or the mask element I was targeting. Will definitely bare that in mind for future animations!