I am having the same thing happen. I am now making smaller batches of the CSM+B mix so that it is not sitting in the fridge for so long (1.5 tsp / 125 ml).

I also noticed that the trace mix seems to react with the air in the bottle I keep it in... A day after making the mix the plastic bottle is somewhat crushed in such a way that it looks like the air was sucked out of it. Anyone else ever see this? Is something reacting within the bottle?