I hit two stale data problems over the weekend.
Playing in editor on MAC was using old game code. This actually led to corrupt data as well I suspect because of some AActor based data changes in between exes that I committed changes to before realizing there was a problem. Luckily easily remedied. Eventually I deleted everything in Binaries/Mac and it did a full rebuild next time I ran the editor and worked correctly.
Playing on iPhone 5. This time the exe was up to date but data was not updated through multiple launches. Eventually I deleted the Build and Intermediate directories and the proper data made it through to the phone.