Looks like turning off track pre-loading is the solution to this problem, below is a paste of the email i received from customer service in case any of the other options they provided including the basics.
First, we need to have you reboot your phone. Press and hold the power button and then choose "Restart".
After your phone has restarted, then try the Slacker Application again and see if the issue has been resolved.
If the issue has not been resolved, then next we will want to Uninstall/Re-install the Slacker Application on your Phone.
You can uninstall the application by going to the "Settings" of your Phone, then "Applications" (or "Apps") and then find "Slacker" in the list of installed apps and press on it to open. Then click on the "Uninstall" or "Uninstall updates" (if Slacker was preloaded on your phone).
Once the application has been uninstalled, then go to your Apps List, and open up "Play Store" and search for Slacker. Update to the latest version of the application available from the Google Play Store. Please Note Once you have re-installed the application, your username/password will have been removed. You will need to Sign Back into the application with your account information. You can sign back in by opening up Slacker, Pressing the "menu" key on your phone and then go to "Settings" from the popup menu. Then go to Account Information and click on Sign In.
If the issue is not resolved by uninstall/re-installing the application, then we will want to check some settings/gather more information from you about the issue.
Open up the Slacker Application, and then press the "menu" key on your phone, and go into "Settings" from the popup menu. Once you are in the Slacker Settings check the following settings:
1). Audio Quality - Set this to the "Good" setting
2). Track Preloading - Set this to the "Off" setting
3). Resume Play on Startup - Set this to the "Off" setting (unchecked)
If the issues continue happen with the above settings, then the next thing is to try a different connection type.
So, if you are connected via OTA (Carrier Data), then please connect to a Wifi Access spot and try using Wifi. Or if you are on Wifi, try using OTA as a test and see if the issues continue to happen. Please let us know if the issues happen on both OTA and Wifi?
Next, if you have a subscription (Radio Plus or Premium), you can try to Download Content to your phone and see if the playback is better when playing the Music from your phone versus using a Data Connection (OTA or Wifi). You can mark items a station for downloading by going to the station list, pressing and holding on the station name, and choosing "Download Station" from the menu that pops up. Once you have marked your stations, then go to "My Music" and then "Downloaded Content" and choose "Refresh" to perform the actual downloading of the stations to your phone. Once the refresh is complete, you will get a message saying "Refresh Complete".
Hope this helps anyone else having the problem.