Did downloading it again last time fix it? In my experience that error is always due to corruption of the file. We use this CDN for many files and I’ve not heard of corruption from it before.
How soon after the beta announcement post are you downloading the update? How are you downloading the update?
I use a PowerShell script to patch my beta and it worked just now. I’ve also downloaded it manually from the link here and it runs without issue. Toad for Oracle 2025 R3 Beta