I used to get a lovely color using raspberry but right before they stopped selling some people were wondering if they had changed something. They were not getting the same color as they did in the beginning of the pops. Don't know that this helped but your not the only one this has happened too.
For my regular recipe I usually cut the next day after gelling. If I'm making a milk soap or one that doesn't gell, It might take 2 or 3 days before I can cut it. It just depends on what recipe I'm using.