I had a similar problem and these are the steps I took to fix it.
First I deleted the files in "Adobe Premiere Pro Preview Files" for the project in question. I reopened Premiere and it appeared that deleting those files didn't seem to do anything as everything in the project looked the same.
I then disconnected the drive with the footage on it and opened Premiere. When it asked where the footage was, I told it to Offline All. I then went into Preferences > Media and hit Clean for the Media Cache Database. This had to be done because it only cleans the cache for files that are no longer connected with the project (as noted above). I closed and reopened the project, selected everything in the Project window, right clicked and chose Relink Media. I located one file and it relinked the rest automatically.
Now, finally, Premiere is re-conforming all the audio. Hooray!