h264_nvenc scaling: "Impossible to convert between the formats supported by the filter 'graph 0 input from stream 0:0' and the filter 'auto_scale_0'"

[Geremia]

Summary of the bug: Cannot scale with h264_nvenc, but can convert without scaling just fine.
How to reproduce:

% ffmpeg -i in.mp4 -vf "scale_vaapi=w=0.5*iw:h=0.5*ih" -c:v h264_nvenc -c:a copy scaled.mp4
ffmpeg -i in.mp4 -vf "scale_vaapi=w=0.5*iw:h=0.5*ih" -c:v h264_nvenc -c:a copy scaled.mp4
ffmpeg version 6.1.1 Copyright (c) 2000-2023 the FFmpeg developers
  built with gcc 13.2.0 (GCC)
  configuration: --prefix=/usr --libdir=/usr/lib64 --shlibdir=/usr/lib64 --docdir=/usr/doc/ffmpeg-6.1.1/html --mandir=/usr/man --disable-debug --enable-shared --disable-static --enable-gpl --enable-version3 --arch=x86_64 --disable-encoder=aac --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-gnutls --enable-libass --enable-libbluray --enable-libcaca --enable-libcdio --enable-frei0r --enable-openal --enable-libopus --enable-libspeex --enable-libssh --enable-libtheora --enable-libv4l2 --enable-libvidstab --enable-libvorbis --enable-libvpx --enable-libwebp --enable-libmp3lame --enable-opencl --enable-opengl --enable-libopenjpeg --enable-libpulse --enable-libsmbclient --enable-libxml2 --enable-librsvg --enable-vulkan --enable-libdrm --enable-libshaderc --enable-gcrypt --enable-libplacebo --enable-lcms2
  libavutil      58. 29.100 / 58. 29.100
  libavcodec     60. 31.102 / 60. 31.102
  libavformat    60. 16.100 / 60. 16.100
  libavdevice    60.  3.100 / 60.  3.100
  libavfilter     9. 12.100 /  9. 12.100
  libswscale      7.  5.100 /  7.  5.100
  libswresample   4. 12.100 /  4. 12.100
  libpostproc    57.  3.100 / 57.  3.100
[mov,mp4,m4a,3gp,3g2,mj2 @ 0x6fd340] st: 0 edit list: 1 Missing key frame while searching for timestamp: 1001
[mov,mp4,m4a,3gp,3g2,mj2 @ 0x6fd340] st: 0 edit list 1 Cannot find an index entry before timestamp: 1001.
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'in.mp4':
  Metadata:
    major_brand     : mp42
    minor_version   : 1
    compatible_brands: mp42avc1niko
    creation_time   : 2024-03-26T01:00:14.000000Z
  Duration: 01:01:52.31, start: 0.000000, bitrate: 24334 kb/s
  Stream #0:0[0x1](und): Video: h264 (High) (avc1 / 0x31637661), yuvj420p(pc, bt709, progressive), 1920x1080, 24072 kb/s, 29.97 fps, 29.97 tbr, 30k tbn (default)
    Metadata:
      creation_time   : 2024-03-26T01:00:14.000000Z
      vendor_id       : [0][0][0][0]
      encoder         : AVC Coding
  Stream #0:1[0x2](eng): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 255 kb/s (default)
    Metadata:
      creation_time   : 2024-03-26T01:00:14.000000Z
      vendor_id       : [0][0][0][0]
File 'scaled.mp4' already exists. Overwrite? [y/N] y
Stream mapping:
  Stream #0:0 -> #0:0 (h264 (native) -> h264 (h264_nvenc))
  Stream #0:1 -> #0:1 (copy)
Press [q] to stop, [?] for help
Impossible to convert between the formats supported by the filter 'graph 0 input from stream 0:0' and the filter 'auto_scale_0'
[vf#0:0 @ 0x6f4640] Error reinitializing filters!
Failed to inject frame into filter network: Function not implemented
Error while filtering: Function not implemented
[out#0/mp4 @ 0x704380] Nothing was written into output file, because at least one of its streams received no packets.
frame=    0 fps=0.0 q=0.0 Lsize=       0kB time=00:00:00.46 bitrate=   0.0kbits/s speed=6.05x    
Conversion failed!