  In computing the third order terms of the series of powers of the center
manifold at an equilibrium point of a scalar delay differential equation, with
a single constant delay $r>0,$ some problems occur at the term
$w_{21}z^2\bar{z}.$ More precisely, in order to determine the values at 0,
respectively $-r$ of the function $w_{21}(\,.\,),$ an algebraic system of
equations must be solved. We show that the two equations are dependent, hence
the system has an infinity of solutions. Then we show how we can overcome this
lack of uniqueness and provide a formula for $w_{21}(0).$
