Nope.
If you are applying as a temporary foreign worker, you need 2 years (and 3900 hours minimum) or the equivalent of skilled employment. It does not have to be continuous, you have 3 years to complete the minimum employment requirements.
If you are applying as a post-graduate, you need 1 year (and a minimum of 1950 hours) of work experience, to be completed within 2 years. It does not have to be continuous.
There is no requirement anywhere in the CEC program that employment be continuous.