I have mine in the fridge so i am also thinking that the solution when mixing is to cold and needs to be a little warmer to activate fully with the cloud of smoke?
I think you just answered your question!
We know that CLO2 gas will tend to stay in solution when below 11C (52F).
Which brings up the question whether we should be keeping SC and acid in the fridge if making classic MMS? Since MMS activation normally takes place in an open container, with the resultant loss of CLO2 gas if the solutions are above 11C (52F), maybe the doses will be more effective due to more available CLO2. The mixing water would also need to be refrigerated, too. But, more activation time may be required. Measuring CLO2 ppm would tell us.
Interesting....
Or, we could make CDH (in a closed container) and not have this question.