Suppose:

-----------------------------------------

\tracingscantokens=1

\scantextokens{first}

\scantextokens{second}

\bye

-----------------------------------------

and run luatex test.

Then the ( and ) are logged curiously: ( ( ... ))  Why all closing ))
are logged after end command?

If we change \scantextokens to \scantokens, then ( and ) behaves more
logical in log file and in the terminal: ( ) ( ).

Petr Olsak