Odd issue with form validation

Not sure what is happening with this one as it seems to work almost all the time, but from time to time we are being advised that a particular form will not submit.

It couldn't be a simpler form - it is literally just a single tick box to confirm something.

A few users are reporting that when they hit submit they can't, and are seeing a validation error message where the submit button is.

Its really odd, as its the generic 'This field is required' message which isn't included anywhere on the page.

I have attached the php page and a screenshot of what people are reporting below.

If someone could have a look or suggest what the cause might be that would be much appreciated, as I'm completely stumped.

Thank you.

Just to say I have narrowed the issue down to being specific to Firefox.

I have been able to replicate it here using Firefox on a Mac (v 39.0), running Yosemite.

That page is behind a login as well. Can you give me FTP access and a working username and password? That would allow me to go in and test and fix the problem.

See below.

There was an older jquery .js file included on the page. I removed it and it appears to have resolved this issue.

Thanks Ray.