What computer operating system?
What specific audio edit features?
Describe your audio including whether Stereo (2 channel) or 5.1 channel.
What project preset are you using. See Edit Menu/Project Settings/General.
I am assuming the you are trying to apply one of the audio effects under Edit header/Effects/Audio Effects.
I am suspecting a Timeline 5.1 channel audio in a Stereo based project. But the answers will be in the details.
Please consider. If any questions or need clarification on the above, please do not hesitate to ask.