For small sized mason jars, the current could be too high. How big are the jars?
If you look at a formula for current and water volume it would indicate the type of current that you need for the water volume that you are using.
I thought that that generator was meant to do all that correctly unless you did not enter the precise water volume when you set it up. It might be worth measuring the water in one of those mason jars to be sure you have set it correctly.