What version of OneNote are you using?
"It is impossibile that the 5 pdfs on different computers added aren't correct imported."
Nothing is impossible. I need proof, beliefs are for religion. This is an illogical statement. what does 5 computers have to do with it? You have left out important details.
Your logic: The PDF is clean because I believe it. The PDF imported correctly because I believe it.
Yet there is a problem.
It's not uncommon for format conversion to get tripped up by content in a document much less if that copy was not clean because it didn't copy correctly or because of other problems such as bad images or malware.
The Surface or the CPU is at fault because I believe it. The Surface is hardware, the same hardware as on any computer. The same i5 CPU, memory, SSD, etc. as on any other computer. It runs the same software, same Windows, same OneNote etc. It is possible for problems to occur and somehow we have to establish what is true and correct vs what is not.
The Process of Elimination and the relentless application of logic not short circuit thinking will lead to a correct conclusion. The hardware cannot distinguish one PDF from another, that's what Software does. We just need to figure out where it went wrong. Or we can believe in it and assume the problem is caused by the Surface knowingly picking this PDF to perform random helter skelter on the same way every time but of course that's not logical.
Contact Microsoft Support see if they can figure it out, sorry I tried.