How do I remove a mask from the next layer you create?

I created a mask in PS to "texturize" the ground and leave the sky untouched. 

Then I used the NIK plugin Silver Efex Pro 2 to create a black-and-white pic. 

The pic in NIK still acts as if the mask is still active, so when I adjust the "Red" to darken the sky, only the masked part on the ground is affected.

The same happens when I create the mask in ACR instead of PS.

I tried Flatten Image, but that didn't help.

I clearly have no clue, can anyone help me?

Please and thank you!