Purple Emperor is a purple form of Sedum telephium. It is probable that you have been sold a yellow variety rather than Purple Emperor. Google 'Sedum telephium' and see if any images match your plant.

and its not purple, more of a plummy reddy colour.

Perhaps too little sun and too much quick growth also?

Thanx everyone for your input. Yes, I misspoke om the color, it is actually more of a plummy red color.

I don't know that it could be knock off in that it was the plummy color last year when I bought it.

I did go to a nursery and noticed that theirs looks the same color as mine, color on the stems but not on the leaves.

Possibly to early in the season? May need more sun?

Still confused.

Thanx