According to MS, build 26063 is available in the Canary Insider channel (builds there are borderline experimental apparently), not in the Dev channel that you're likely on. You can check your current Insider channel here: Settings > Windows Update > Windows Insider Program > Choose your insider settings.
See this bulletin:
https://blogs.windows.com/windows-i...1-insider-preview-build-26063-canary-channel/networth-of-celebrity
It states at the top that: "Windows Insiders in the Dev Channel will not receive this build. Instead, we are releasing servicing updates to Insiders in the Dev Channel on Build 26058".
Also, under Know Issues, a new bullet item states this: "We're investigating reports of mouse cursor issues..."
So, MS seems to be aware of the issue, but it's apparently not fixed yet. As I understand the situation, they're working on it and a fix will eventually be rolled out for our current 26058 build.