Laurie,
Yes, that IS normal. Although current is the same in both cables, you will FEEL the current more, and the EFFECT is stronger in the red anode (positive) cable than the black cathode (negative) cable.
This does allow the hand (or foot) being treated by the red cable to get “more effective” current and therefore go through the initial treatment phase quicker.
In the long run when you are in the maintenance treatment phase, it does not really make a difference, but you can alternative hands (or cables) in the initial stage to have a more even treatment and help both hands reach effectiveness quicker together.
I hope that makes sense!
Chris