Hi,
We try the command on AGX Thor developer kit(RT kernel and non-RT kernel) but do not observe the issue:
nvidia@nvidia-ppcc:~$ gst-launch-1.0 -ev videotestsrc num-buffers=150 is-live=1 ! video/x-raw,format=I420,width=1920,height=1080 ! nvvidconv ! nvv4l2h265enc ! fpsdisplaysink text-overlay=0 video-sink=fakesink sync=0
Setting pipeline to PAUSED ...
Opening in BLOCKING MODE
Pipeline is live and does not need PREROLL ...
/GstPipeline:pipeline0/GstFPSDisplaySink:fpsdisplaysink0/GstFakeSink:fakesink0: sync = false
Pipeline is PREROLLED ...
Setting pipeline to PLAYING ...
New clock: GstSystemClock
/GstPipeline:pipeline0/GstVideoTestSrc:videotestsrc0.GstPad:src: caps = video/x-raw, format=(string)I420, width=(int)1920, height=(int)1080, framerate=(fraction)30/1, multiview-mode=(string)mono, pixel-aspect-ratio=(fraction)1/1, interlace-mode=(string)progressive
/GstPipeline:pipeline0/GstCapsFilter:capsfilter0.GstPad:src: caps = video/x-raw, format=(string)I420, width=(int)1920, height=(int)1080, framerate=(fraction)30/1, multiview-mode=(string)mono, pixel-aspect-ratio=(fraction)1/1, interlace-mode=(string)progressive
/GstPipeline:pipeline0/Gstnvvconv:nvvconv0.GstPad:src: caps = video/x-raw(memory:NVMM), width=(int)1920, height=(int)1080, framerate=(fraction)30/1, pixel-aspect-ratio=(fraction)1/1, format=(string)I420, multiview-mode=(string)mono, interlace-mode=(string)progressive
/GstPipeline:pipeline0/nvv4l2h265enc:nvv4l2h265enc0.GstPad:src: caps = video/x-h265, stream-format=(string)byte-stream, alignment=(string)au, profile=(string)NULL, level=(string)NULL, width=(int)1920, height=(int)1080, pixel-aspect-ratio=(fraction)1/1, framerate=(fraction)30/1, interlace-mode=(string)progressive, colorimetry=(string)bt709, chroma-site=(string)mpeg2, multiview-mode=(string)mono, multiview-flags=(GstVideoMultiviewFlagsSet)0:ffffffff:/right-view-first/left-flipped/left-flopped/right-flipped/right-flopped/half-aspect/mixed-mono
/GstPipeline:pipeline0/GstFPSDisplaySink:fpsdisplaysink0.GstGhostPad:sink.GstProxyPad:proxypad0: caps = video/x-h265, stream-format=(string)byte-stream, alignment=(string)au, profile=(string)NULL, level=(string)NULL, width=(int)1920, height=(int)1080, pixel-aspect-ratio=(fraction)1/1, framerate=(fraction)30/1, interlace-mode=(string)progressive, colorimetry=(string)bt709, chroma-site=(string)mpeg2, multiview-mode=(string)mono, multiview-flags=(GstVideoMultiviewFlagsSet)0:ffffffff:/right-view-first/left-flipped/left-flopped/right-flipped/right-flopped/half-aspect/mixed-mono
/GstPipeline:pipeline0/GstFPSDisplaySink:fpsdisplaysink0/GstFakeSink:fakesink0.GstPad:sink: caps = video/x-h265, stream-format=(string)byte-stream, alignment=(string)au, profile=(string)NULL, level=(string)NULL, width=(int)1920, height=(int)1080, pixel-aspect-ratio=(fraction)1/1, framerate=(fraction)30/1, interlace-mode=(string)progressive, colorimetry=(string)bt709, chroma-site=(string)mpeg2, multiview-mode=(string)mono, multiview-flags=(GstVideoMultiviewFlagsSet)0:ffffffff:/right-view-first/left-flipped/left-flopped/right-flipped/right-flopped/half-aspect/mixed-mono
/GstPipeline:pipeline0/GstFPSDisplaySink:fpsdisplaysink0.GstGhostPad:sink: caps = video/x-h265, stream-format=(string)byte-stream, alignment=(string)au, profile=(string)NULL, level=(string)NULL, width=(int)1920, height=(int)1080, pixel-aspect-ratio=(fraction)1/1, framerate=(fraction)30/1, interlace-mode=(string)progressive, colorimetry=(string)bt709, chroma-site=(string)mpeg2, multiview-mode=(string)mono, multiview-flags=(GstVideoMultiviewFlagsSet)0:ffffffff:/right-view-first/left-flipped/left-flopped/right-flipped/right-flopped/half-aspect/mixed-mono
Redistribute latency...
/GstPipeline:pipeline0/nvv4l2h265enc:nvv4l2h265enc0.GstPad:sink: caps = video/x-raw(memory:NVMM), width=(int)1920, height=(int)1080, framerate=(fraction)30/1, pixel-aspect-ratio=(fraction)1/1, format=(string)I420, multiview-mode=(string)mono, interlace-mode=(string)progressive
/GstPipeline:pipeline0/Gstnvvconv:nvvconv0.GstPad:sink: caps = video/x-raw, format=(string)I420, width=(int)1920, height=(int)1080, framerate=(fraction)30/1, multiview-mode=(string)mono, pixel-aspect-ratio=(fraction)1/1, interlace-mode=(string)progressive
/GstPipeline:pipeline0/GstCapsFilter:capsfilter0.GstPad:sink: caps = video/x-raw, format=(string)I420, width=(int)1920, height=(int)1080, framerate=(fraction)30/1, multiview-mode=(string)mono, pixel-aspect-ratio=(fraction)1/1, interlace-mode=(string)progressive
Redistribute latency...
/GstPipeline:pipeline0/GstFPSDisplaySink:fpsdisplaysink0/GstFakeSink:fakesink0: sync = false
/GstPipeline:pipeline0/GstFPSDisplaySink:fpsdisplaysink0: last-message = rendered: 18, dropped: 0, current: 34.19, average: 34.19
/GstPipeline:pipeline0/GstFPSDisplaySink:fpsdisplaysink0: last-message = rendered: 33, dropped: 0, current: 30.00, average: 32.15
/GstPipeline:pipeline0/GstFPSDisplaySink:fpsdisplaysink0: last-message = rendered: 48, dropped: 0, current: 30.00, average: 31.44
/GstPipeline:pipeline0/GstFPSDisplaySink:fpsdisplaysink0: last-message = rendered: 64, dropped: 0, current: 30.00, average: 31.07
/GstPipeline:pipeline0/GstFPSDisplaySink:fpsdisplaysink0: last-message = rendered: 79, dropped: 0, current: 29.95, average: 30.85
/GstPipeline:pipeline0/GstFPSDisplaySink:fpsdisplaysink0: last-message = rendered: 95, dropped: 0, current: 30.00, average: 30.70
/GstPipeline:pipeline0/GstFPSDisplaySink:fpsdisplaysink0: last-message = rendered: 110, dropped: 0, current: 30.00, average: 30.61
/GstPipeline:pipeline0/GstFPSDisplaySink:fpsdisplaysink0: last-message = rendered: 126, dropped: 0, current: 30.00, average: 30.53
/GstPipeline:pipeline0/GstFPSDisplaySink:fpsdisplaysink0: last-message = rendered: 142, dropped: 0, current: 30.00, average: 30.47
Got EOS from element "pipeline0".
EOS received - stopping pipeline...
Execution ended after 0:00:05.129106958
Setting pipeline to NULL ...
Freeing pipeline ...
Please give it a try. If the issue persists, please try to remove nvidia-l4t-gstreamer deb package, re-install it and clean the cache.