Instructions on turning it off can be found here: Problems caused by Windows Defender (strange behavior when using Opus)
There are two parts of it, which is often missed.
If it (or similar privacy guard software) objects to some of the content of the file (e.g. because it looks like personal data), that could explain why it goes wrong with some files and not others. But that's just a theory; the cause might turn out to be something else.
If you can log one of the failed updates with Process Monitor, that might reveal what's going wrong.
Device type could also play a part (e.g. non-Windows NAS or unusual filesystems can do strange things).