[Bug] Flashing green dash

[fu-hsi]

Hi.
It could be a plugin bug, or ffmpeg itself.
This is random, doesn't always occur, but once it occurs, it continues for the full length of the clip.

My commands (only necessary):

ffmpeg -n -i %%a -vf vidstabdetect=shakiness=10:accuracy=15:result="%%~na.trf" -f null -
ffmpeg -n -i %%a -vf vidstabtransform=input=%%~na.trf:zoom=7:optzoom=0:smoothing=20:interpol=bicubic,unsharp=5:5:0.8:3:3:0.4,scale=1920:1080 -c:v h264_qsv -q 17 -c:a copy "stab_1080p\%%~na.mp4"

Version:

ffmpeg version 2020-11-04-git-cfdddec0c8-essentials_build-www.gyan.dev Copyright (c) 2000-2020 the FFmpeg developers
built with gcc 10.2.0 (Rev3, Built by MSYS2 project)
configuration: --enable-gpl --enable-version3 --enable-static --disable-w32threads --disable-autodetect --enable-fontconfig --enable-iconv --enable-gnutls --enable-libxml2 --enable-gmp --enable-lzma --enable-zlib --enable-libsrt --enable-libssh --enable-libzmq --enable-avisynth --enable-sdl2 --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxvid --enable-libaom --enable-libopenjpeg --enable-libvpx --enable-libass --enable-libfreetype --enable-libfribidi --enable-libvidstab --enable-libvmaf --enable-libzimg --enable-amf --enable-cuda-llvm --enable-cuvid --enable-ffnvcodec --enable-nvdec --enable-nvenc --enable-d3d11va --enable-dxva2 --enable-libmfx --enable-libgme --enable-libopenmpt --enable-libopencore-amrwb --enable-libmp3lame --enable-libtheora --enable-libvo-amrwbenc --enable-libgsm --enable-libopencore-amrnb --enable-libopus --enable-libspeex --enable-libvorbis --enable-librubberband
libavutil      56. 60.100 / 56. 60.100
libavcodec     58.112.101 / 58.112.101
libavformat    58. 64.100 / 58. 64.100
libavdevice    58. 11.102 / 58. 11.102
libavfilter     7. 88.102 /  7. 88.102
libswscale      5.  8.100 /  5.  8.100
libswresample   3.  8.100 /  3.  8.100
libpostproc    55.  8.100 / 55.  8.100

But the older version generated the same problem.