When building a world, the SDK validator may attempt to read and "validate" editor-only scripts which do not include any reference to UDON or VRC. What's worse, is the "validator" will misinterpret a larger number of explicitly non-UDON scripts over time.
This has been a problem since at least the start of using Unity 2022, but it appears to get worse over time without updates, suggesting it is an issue that has gone ignored for some time and somehow "leaks" something and now it's causing issues in long-term maintenance of worlds.