Fixed IP addresses change and are deprecated all the time. It's of zero concern to APNIC that customers of Cloudflare or various ISPs can no longer access the internet because they relied on a temporary IP assignment, after the service was gracefully terminated and deprecated, with ample lead time.

That being said, the use by Cloudflare is an excellent way to reclaim this part of the IP space, I don't see why they would terminate this collaboration.