A coherent explanation of problem would be nice.
Are you using measure as bench mounted? If you are trying to use it as case-activated, about all I can say is to read ALL the Lee instructions and follow them.
The measure does leak when new with small kernel powder.
You need to work a bunch of graphitized or even powdered graphite through it.
You need to disassemble and remove all powder kernels and set the tension higher before you add powder. Do not adjust tension with powder in the press.
As a bench mounted measure, you put a piece of paper under the measure to catch any leakage.
After a while, the two conical sections burnish to each other and leakage will disappear.
After the measure has been 'worn' in, then it should be good to go with the case activated tooling.
Again, though, if your leakage is the powder NOT flowing down the drop tube, we would need some more information to help understand.