PHP Notices are logged when mact is called without parameters, or with
insufficient parameters.

URL: https://www.m.co.uk/index.php?mact

Errors:
[23-Jun-2017 13:32:33 Europe/London] PHP Notice:  Undefined offset: 1 in
/var/sites/m/m.co.uk/public_html/lib/page.functions.php on line 523
[23-Jun-2017 13:32:33 Europe/London] PHP Notice:  Undefined offset: 2 in
/var/sites/m/m.co.uk/public_html/lib/page.functions.php on line 523
[23-Jun-2017 13:32:33 Europe/London] PHP Notice:  Undefined offset: 3 in
/var/sites/m/m.co.uk/public_html/lib/page.functions.php on line 523

Line 523 of page.functions.php explodes the mact request variable and sends to
list without checking if the variable has enough parameters:

list($module,$id,$action,$inline) = explode(',',$_REQUEST['mact'],4);

Perhaps can be solved by prepending with:

if( count(explode(',',$_REQUEST['mact'],4)) != 4 ) return;