This is just a warning. It is OK.
The failure happens with the pipeline you post in another topic Multiple cameras use nvdewarper
Can the original pipeline work with your DeepStream 7.1?
gst-launch-1.0 v4l2src device=/dev/video0 do-timestamp=true ! \
queue max-size-buffers=8 max-size-time=0 max-size-bytes=0 ! \
nvvideoconvert ! \
nvdewarper config-file=/home/ubuntu/workspaces/deep_stream_view/DeepStream-gi/configs/config_dewarper.txt source-id=6 ! \
m.sink_0 nvstreammux name=m width=1920 height=1080 batch-size=1 num-surfaces-per-frame=1 ! \
nvmultistreamtiler ! \
nv3dsink sync=false max-lateness=5000000