Adaptive noise reduction - 5.1 sound

Hello.

I have been using adobe premiere for months now and I´ve been using adaptive noise reduction effect with 5.1 sound pretty much all the time. Never had any problems...However a few days ago I updated the program and now I cannot use the effect on 5.1 sounds anymore. I saw a small text saying the effect can only be applied to mono or stereo. I tried using the effect on 5.1 sounds that I am certain I have used it on before and it cannot be done anymore. Is anyone else having this problem?

Thank you in advance for your help and answers.