Seems a workaround is just adding queue after nvarguscamerasrc:
gst-launch-1.0 nvarguscamerasrc ! 'video/x-raw(memory:NVMM),format=NV12,width=3264,height=1848,framerate=28/1' ! queue ! nvvidconv ! video/x-raw,format=I420 ! nvvidconv ! 'video/x-raw(memory:NVMM),format=I420' ! nvjpegenc ! fakesink
[EDIT: this workaround doesn’t work with EOS].
[EDIT2: Seems a workaround for nvjpegenc with EOS is rather using queue before nvjpegenc:
gst-launch-1.0 -ev nvarguscamerasrc ! 'video/x-raw(memory:NVMM),format=NV12,width=3264,height=1848,framerate=28/1' ! nvvidconv ! video/x-raw,format=I420 ! nvvidconv ! 'video/x-raw(memory:NVMM),format=I420' ! queue ! nvjpegenc ! fakesink
]