Yes, the leaves on Skimmia often start out with a reddish tinge then turn green as they mature.

Spirea Magic Carpet has these leaves, red tinged yellow when they emerge.

My brain is definitely going mushy. I meant Spiraea not Skimmia, sorry.

there are a few half green and half yellow. and yes this is not unusual its just the way the pigment has been distributed.

I get leaves on my spiraea 'Goldflame' that do this as well.

Thanks for your replies, although I was beginning to wonder if Owdboggy was on the same page as the rest of you..lol
I rather like these leaves, I have a spirea in my front garden that I thought was the same one but it's leaves are all one colour.