Hi,
Please apply this and give it a try:
Jetson/L4T/r32.5.x patches - eLinux.org
[camera] 3rdparty application fails to open with USB camera
The prebuilt lib is mainly for launching USB camera, but it also helps a usecase which usese nvv4l2decoder:
Gstreamer and v4l2loopback - #5 by DaneLLL