No. The transcription process is on the internet (within the ‘cloud’), and hence this will happen only if connected to the internet. The stenographer will be unable to even sign in. No files can be accessed. With portable Wi-Fi devices including the smartphone, this should never be a barrier.
Please note that for the team, once signed in to the smartphone app, they will be able to dictate even if offline. The files will be saved as drafts. The users can choose to upload as feasible.