When you use the Stryd app on your phone to upload your activities to PowerCenter, it can take some time for your run to appear. At times, our servers are busy and activities do not upload immediately. The Stryd app will have queued these activities.
Because you already got the data from your device, another attempt to get data from Stryd will result in a message "no run data found". Even though this message appears, your run data is still safely stored on your phone and will upload to PowerCenter eventually.