• On all OpenSSL versions

The documentation for SSL_CERT_DIR (https://docs.openssl.org/3.5/man1/openssl-rehash/#options)
Is wrong for Windows, the documentation states:
Colon separated list of directories to operate on.

But in fact on Windows the separator is Semicolon
https://github.com/openssl/openssl/blob/master/include/internal/e_os.h#L142