Nvidia 1660Super, ubuntu 18.04lts server: "No devices found."

Hi, I use cuda to convert videos with ffmpeg, with the extension h264_nvenc.
Unfortunately it often happens that ffmpeg reports the error:
"[h264_nvenc @ 0x55c4aafb9900] dl_fn-> cuda_dl-> cuInit (0) failed -> CUDA_ERROR_NO_DEVICE: no CUDA-capable device is detected
Error initializing output stream 0: 0 - Error while opening encoder for output stream # 0: 0 - maybe incorrect parameters such as bit_rate, rate, width or height
Conversion failed! "

The nvidia-smi -L command gives me as output: “No devices found.”.

If I try to use the “nvidia-smi -L” command several times, after many “no devices found” errors, the video card is recognized and I have this output "GPU 0: Graphics Device (UUID: GPU-6c687676- 7a64-a6c1-1784-e74f710abad0) ", and at this point ffmpeg works.

The system is currently unstable and I am unable to convert automatically.

I attach log created with nvidia-bug-report.
nvidia-bug-report.log.gz (447 KB)