frequency vectors from cwt

I am running cwt with Morlet wavelets with this code:

 for i=1:size(signal,3)
     for ii = 1:size(signal,1)
     [coef(:,:,ii,i),freq(:,:,ii,i),~] = cwt(signal(ii,:,i),wname,'NumOctaves',numOctaves,'VoicesPerOctave',numVoices,fs);

     end
 end

However, the frequency vectors appear to change depending on the value of ii and i. I don't understand this because we are using the same algorithm with the same parameters at each step. This means I cannot average across EEG trials because the psuedofrequencies do not line up. Has anyone ever experienced this problem? Thanks