Discount and vouchers overlaping

[Joe Michael]

So this is the setup:

I have a temporary 20% discount on all products until 30'th of August defined as a catalog price rule, but i want to make a permanent 30% voucher discount. 

 

What happens is that on cart when i apply the voucher i get 50% discount. 

 

Are there any kind of dependencies, or is there a way to forbid presta from using the specific price discount if a voucher is applied. 

 

I know it could be done with different voucher with one applied automatically but it's not my prefferable choise cause i want the discount to bi visible in products, not only in cart.

 

Any help appreciated!