Is it possible that this might be occurring because there is not enough storage on your device? Pandora will never use the last 500MB of storage on your device, so we will only download as many stations as we can before we hit that limit.
If it doesn't appear to be storage related, I'd recommend disabling the offline listening feature and re-enabling it, which will reset the download process. Then, make sure to keep Pandora in the foreground of your device while the download completes.
To do that from a mobile device:
Tap the Profile tab and then the Settings gear in the top right corner.
Toggle Offline Mode off, and confirm that you'd like to remove the content from your device.
Toggle Offline Mode on again, to reset the download process.
Keep the Pandora app in the foreground of your device while your offline stations re-download.
If you continue to have trouble, please send over a screenshot showing the status of the downloads:
Tap theProfiletab and then theSettingsgear in the top right corner.
Next selectOffline. You should now be able to view a progress bar indicating the current download status.
Take a screenshot of what you see here and attach it to your direct reply to this email.