Default app Chomp SMS not saving
Or for example on Huawei.
If you have Chomp SMS as default app for sms, you may need to set Chomp SMS as a "protected app" (not to kill it after locking the phone). Then your SMS will be okay and delivered. The default app by Huawei doesn't need to be as a protected app and it's still running. But Chomp SMS is killed by locking the phone.
Thanks heaps!