Bug 162642

man rc.subr says:

     run_rc_script file argument
           Start the script file with an argument of argument, and handle the
           return value from the script.

           Various shell variables are unset before file is started:

                 name, command, command_args, command_interpreter,
                 extra_commands, pidfile, rcvar, required_dirs,
                 required_files, required_vars, argument_cmd, argument_precmd.
                 argument_postcmd.

           The startup behaviour of file depends upon the following checks:

           1.   If file ends in .sh, it is sourced into the current shell.

           2.   If file appears to be a backup or scratch file (e.g., with a
                suffix of ~, #, .OLD, or .orig), ignore it.

           3.   If file is not executable, ignore it.

           4.   If the rc.conf(5) variable rc_fast_and_loose is empty, source
                file in a sub shell, otherwise source file into the current
                shell.

This is only true for .sh scripts sitting in /etc/rc.d
but not for other locations.

How-To-Repeat: 
put test.sh into /usr/local/etc/rc.d and it will get executed
in a subshell but not executed in the current shell.