[R=301]tells mod_rewrite that the request should be redirected, but the request will not be redirected instantly. It will evaluate the rules until it finds a flag [L]or [END](or gets to the end of the file). Now it matches the first rule and says that when mod_rewrite feels ready, it should redirect. mod_rewrite has not yet found a flag Lor ENDand still has rules to match. Then it will comply with the second rule and will include a redirect.
[R=301,L], . .htaccess, . .