[Unrealpak patching] hashing differences after re-cooking the same content

Hi,

I’m trying to get patching of pak files working using unrealpak and I’m coming across an issue where a specific list of files fails the hash check after re-cooking. To test this I performed a full cook and pak of the content, archived this pak and then performed a re-cook of the same content with a manual call to unrealpak, passing the archived pak file via the ‘-generatepatch=’ switch.

The original pak file has 21k+ assets and 245 get rejected duration hashing ‘Source file hash for [file] doesn’t match dest file hash…’. A binary diff shows minor modifications to these files but I’ve no idea what is being modified or why when the content and build config isn’t changed…?

Is the pak patching system usable or is there something during the cook stage that renders it unreliable for patching?

Does anyone know what could be dirtying content each cook?

Thanks,

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