Will K-1's from actively participating members of an LLC be subject to S/E Taxes?

My CPA says that as an active partner of an LLC that has a fairly decent profit, I am required to pay Self-Employment taxes on the so called "K-1 distributable share of income."

Is this correct? Because, I also have an S Corporation and the K-1 from the S-Corporation is not subject to S/E taxes?

This should not be the case, as the LLC has been touted as a better Entity!!