I can assure you that if the problem were in the script, the Footer widget would not work at all. It is not possible for the same code to work occasionally and then not work. I think the problem is your server load, or your website is too heavy (a lot of active plugins and scripts) so it takes more time to load your website. There’s nothing we can do about it.
The code is good and works properly on all other sites.
But, as I promised you before, I will forward your request to our developers to check it out.