24 fps question

[Uptight]

Noob question since I don't understand about the technical stuff: if all movies are shot at 24 fps and the majority of discs present these contents at 23.976 fps, a "well defined robust standard" according to some, then why some random UHDs/Blu-rays are at 24 fps?????????

If we try to put any audio track in sync with the old media, it will be out of sync with the 24 fps.

Are these 24 fps discs exclusive to Europe and not from NTSC territory?