Just tried switching to python and that seems to work e.g.
# Add a new field called 'myNewField' to the JSON of the item
_input.item.json.myNewField = 1
return _input.item
But with the same in javascript nothing:
// Add a new field called 'myNewField' to the JSON of the item
$input.item.json.myNewField = 1;
return $input.item;
Is there still a problem with TaskRunners as described here: Issue with Code Node Timeout in n8n Cloud - #6 by Kivema