I had this issue as well, after some sleuthing around I found this solution and it seems to have helped me in stopping this log file from filling up with these Nvidia logs. While editing the Plex docker image, in the Extra Parameters field under Advanced View options add
"--no-healthcheck"
I am still unsure what causes the logs, but after adding that I have haven't had any issues and the file stays roughly the same size without filling up the TMPFS partition.