TR Fit files exhibit ridiculously high speeds

First thought is to confirm the wheel size you have entered into the Settings of your TrainerRoad app/device. A typical road tire setup is 2096mm (for 700x23) or 2105mm (for 700x25) IIRC.

Next consideration is the potential for altered values via ERG mode (if used) and gearing in use)

After that, it might be related to a bug listed in a thread just moments ago.