Hello and thank you for report. Do you use the itchio app or did you try to download it from the website?
From the website
Seems to not be the only link that is buggy though, so it might be an issue with the website.
I checked other random demos, and yeah, it works half of the time. So no worries, probably not your bug.
Well, we never had such a bug report which probably means there are web site issues so hopefully it works for you soon~