Reproduction link or steps

REPL

Note that this only happens on Windows, you need to download the project and run it locally to reproduce

What is expected?

No error happens like Rollup

What is actually happening?

The following error happens

[INVALID_OPTION] Invalid substitution "/favicon" for placeholder "[name]" in "entryFileNames" pattern, can be neither absolute nor relative paths.

System Info

REPL 1.1.4

Any additional comments?

The same error happens with \\favicon.ico. But doesn't happen with C:\\favicon.ico.

Originally reported at vitejs/vite#22889