Thank you for your reply, no i was comparing the hash of both files, the file before i add it then the file out, after downloading it from here: https://ipfs.infura.io/ipfs/QmTCP7Ln1PL…
The hash of the downloaded file, when i hash it in a sha256 tools was different than the hash of the initial file. Figured out the file was incomplete after the add, for exemple it missed the background compare to the initial PDF file… no idea why.
Then i changed lib, from ipfs-mini to ipfs-http-client and its working ok now, both files, in and out have same hash.
Ok thanks for the info, i though all these gateway were public and could be used to add file like with ipfs.infura.io, so there is only one public gateway/point of entry allowing add? Best practice is to setup my own gateway?