Hash not matching with two different ffmpegs versions used to merge videos

[Hammer]

I know about encoding etc. but since I want to make sure I have all the videos downloaded and stored in a way I can confirm they're "perfect"(no missing fragments or IO errors) I tried to sha the file I merged using the newest version of ffmpeg and I found out they mismatch I tried to check them with a hex editor and I found out that the only different part is at the end:

Lavf60.11.100 with ffmpeg version 16 10 2023
Lavf60.15.100 with ffmpeg version 07 09 2023
Lavf60.17.100 with ffmpeg version 02 11 2023

The command used is always the same:

ffmpeg.exe -i "video.mp4" -i "audio.m4a" -c copy "test.mp4"

Is there a switch to avoid ffmpeg appending this text at the end of the file? If not can I remove it manually without causing data loss? Is it important? Thanks in advanced
Sorry if it's a dumb question, but I'm a noob and I want to understand better how these things work and how I can hash them knowing they'll be the same even if I merge the audio and video with the newest version and I compare it with the old version merged. Thank you for your patience if you read till here.

If you want to recreate this just run this:

yt-dlp "https://zavideoplatform.streaming.mediaservices.windows.ne t///7ea4f3d7-2776-43a5-86e1-c05862349e8e/Introduction.ism/manifest(format=m3u8-aapl-v4)"
0907ffmpeg.exe -i "manifest(format=m3u8-aapl-v4) [manifest(format=m3u8-aapl-v4)].faudio-aac_eng_2_127999_2_1.mp4" -i "manifest(format=m3u8-aapl-v4) [manifest(format=m3u8-aapl-v4)].faudio-aac_eng_2_127999_2_1.mp4" -c copy "0907.mp4"
1016ffmpeg.exe -i "manifest(format=m3u8-aapl-v4) [manifest(format=m3u8-aapl-v4)].faudio-aac_eng_2_127999_2_1.mp4" -i "manifest(format=m3u8-aapl-v4) [manifest(format=m3u8-aapl-v4)].faudio-aac_eng_2_127999_2_1.mp4" -c copy "1016.mp4"
1102ffmpeg.exe -i "manifest(format=m3u8-aapl-v4) [manifest(format=m3u8-aapl-v4)].faudio-aac_eng_2_127999_2_1.mp4" -i "manifest(format=m3u8-aapl-v4) [manifest(format=m3u8-aapl-v4)].faudio-aac_eng_2_127999_2_1.mp4" -c copy "1102.mp4"
certutil -hashfile 0907.mp4 SHA256
certutil -hashfile 1016.mp4 SHA256
certutil -hashfile 1102.mp4 SHA256
pause

Where:
0907ffmpeg.exe is the ffmpeg published on 07 09 2023
1016ffmpeg.exe is the ffmpeg published on 16 10 2023
1102ffmpeg.exe is the ffmpeg published on 02 11 2023

[Secoast]

You could try demuxing the streams, and hashing those. Created date etc, and some other exif info should be ignored by the hash, but a single comma removed in a novel sized doc can change the hash produced, so it doesn't take much.