EDIT (Last one I hope)
Moderators
pls move post as confirmed as NOT a bug
--------------------- below is original thoughts on bug possibility--------------
fmpeg --help
ffmpeg: relocation error: /usr/local/lib/libavfilter.so.3: symbol av_get_channel_layout_channel_index, version LIBAVUTIL_51 not defined in file libavutil.so.51 with link time reference
cheers