[HELP] Hybrid introducing audio delay that is not present in source material

[4i4oVi40]

Using a delay of 40:

MP4Box -add "E:\Output\video.m4v"#video:fps=25_delay=40:name="":lang="" -add "E:\Output\audio.aac"#audio:name="":lang="" -mpeg4 -itags tool="Hybrid 2021.10.15.1" -tmp "E:\Output" -new "E:\Output\faac_40.mp4

You have a typo, "_" instead of ":". You have fps=25_delay=40. It should be fps=25:delay=40. This may be the problem.