Although immediate duration tests should be completed by the set duration, there are other internal factors that need to to be met on the device prior to execution which can delay the execution of the duration test.
Due to these possible delays, this can lead to some device results still being pending at time of collection. If you believe the results could be ready you can request a resync to get the results.
The app will alert you to go and sync the devices for the pending results after the timeout settings you have provided in the app.
To adjust this timeout you can find the setting under:
Site dashboard -> Details -> Edit -> Settings > Test execution timeout (days)