Rails4 ActionController::InvalidAuthenticityToken error

Question

I have Rails4 application running in production, and my visitors run occasionally into ActionController::InvalidAuthenticityToken error, which I cant reproduce. I get 2-4 daily

Answer 1

Since rails uses JavaScript to append the authenticity_token to rails forms, I would double-triple check that you don't have a runtime JS error based of of dynamic content that is causing this heisenbug. If a JS error we're to break the whole application.js file, your forms would be invalid. Is this possible?