After some additional testing, the networks must be created by starting with an initial blank dlnetwork which seems to only work in 2024a.
% Create the Layer Graph
criticNetwork = dlnetwork;
criticNetwork = addLayers(criticNetwork,obsPath);
criticNetwork = addLayers(criticNetwork,actPath);
criticNetwork = addLayers(criticNetwork,commonPath);
If you create a layerGraph and convert to a dlnetwork afterwards the initialize function won't initialise with a different set of weights. If you have scripts to create networks from previous MATLAB versions you may need to change the structure to create them as blank dlnetwork objects first when using identical SAC critics!