It is surprising that a company like Honda can upload a corrupt PDF file, I am a software developer and if I did not test things like this before going live my clients would not be my clients for much longer!
They say it will take a few days to fix, they should at least remove the link to the broken 2018 file and perhaps replace with a message "2018 Manual coming soon" so they can re-upload the PDF once they have fixed it.
I hope they put more attention to detail into designing and building their cars?