Just found this "new" behavior while upgrading an old instance from ORDS 2.10 to 17.4.1.
Suddenly some REST webservices defined via APEX SQL Workshop didn't work anymore. They produced a 404 not found message: The procedure named ragtest could not be accessed, it may not be declared or the user executing this request may not have been granted execute privilege on the procedure. Check the spelling of the procedure and check that the execute privilege has been granted to the caller
Turns out, the URI template didn't have a trailing slash.
Under ORDS 2.x this wasn't required, somewhere in 3.x it must have started to need that, since I could reproduce that behavior also on apex.oracle.com which runs ORDS 3.10
Once the trailing slash is added, the webservice works fine again.
To me it feels like a bug, what do you think?