After you have made changes to your show you will need to publish those changes in order for the respective changes to be available across all platforms that pull your show.
When you make a change to an episode you will see a little 'i' symbol next to Publish Settings:
Click Publish Settings then you should be navigated to the publish area where you can publish changes:
Doing this will cause all platforms that has your show to update accordingly. Changes you have made will not be reflected immediately after you have published changes, this is normally because it may be cached. For more information regarding this, please see this article.
If I replace an audio file will that affect my stats?
If you replace your audio file and publish the changes, this will simply swap out the audio file for all platforms meaning that users will get the latest updated episode. This won't affect your stats in any way.
Tip: If you have made a change and it has not pulled through, it is normally good to double check on Acast to see if the Publish Changes icon is there.