On the Adobe Media Encoder, When I used the Mercury Playback Engine GPU (CUDA) the exporting stop at 3 seconds but if I used the Mercury Playback Engine GPU (OPEN CL) as renderer it works and I can multi-task. Before I can use the (CUDA) on my exports but after an update on Adobe Premiere Pro 2020 14.8 and Adobe Media Encoder it suddenly becomes like that. I have reverted my version on 14.6 but I still experience the same problem?
There have been a bunch of users on here in the last few days with crash/hangs/playback issues with Nvidia GPUs installed. There is clearly a buggy Nvidia 'game' driver out there.
Go to the Project settings dialog, Mercury Acceleration and set to software only. If that works, and CUDA still doesn't, then go to the Nvidia site. Download/install the latest STUDIO driver in a clean install. You may need to roll back even one Studio driver version. Some users can work with the newest Studio driver, some need to go back one.