This is not the issue in CE or VLC. The issue is in your hevc file, especially in meta data are missing aspect ratio values. In this case the video is scaled to cover whole screen. The hevc issue for non-standard AR is only in old 3.14 kernel, where decoder is unable provide AR info and kodi is using bitstream converter to retrieve AR. But there is bitstream converter implemented only for mpeg2 and h264.
You can verify hevc behavior by switching off hw decoding to use sw decoding (ffmpeg). ffmpeg is commonly used by kodi for sw decoding in all platform and AR is correctly implemented.