I hear about instances like this a lot. Did a broken request just resolve to the contents of the file that created it, or did it just spit itself out in your browser console?
I enjoy how transparent client-side apps are these days. I remember trying to order something from an online store, and the "submit" button wouldn't work because some third-party license key wouldn't validate (I think it was to load a map to show your own address?), and that error stopped the actual sending of the HTTP request to submit an order. I patched that out and submitted my order. Easier than finding their email address and waiting a week for their contractors to fix it.