Yeah…
For what I see, after have scanned all the photo media, Is that not recently photo are involved but only ones coming from the old phone of my GF (2019/2020); and those photos are not uploaded by nextcloud but just sitting there (giving her the sensation to have everything in one place 
). And make a lot of sense that something goes wrong during the initial transfer.
Just 1 only photo founded in another pool but same source.
The annoyng thing now Is that, going deeper in the file checks, i discovered that some video are corrupted too. Same origin of the photo. Don’t think i can use python there to achieve the check massively, gonna found a solution.
The things that scare me instead Is the possibility that some corrupted file can be backupped on good file.