After Loading Custom Blocks and Random Groups for the first time, when you load strategies in AW or Builder that uses those Custom Blocks, it will always ask you to 'Use existing in SQ' or 'Use from loaded'.
If you put 'Use existing in SQ' and your strategy contains randomized values, your random values will be not loaded and will load a default value.
Random Values will only be loaded only if you put 'Use from loaded'.
So if I want to prevent this issue, I had to put all my Random Groups in one strategy in AW, then save it. Then load the strategy and click 'Use from loaded' in all those the custom blocks I have.