The quick translation feature often loads hundreds of fields for translations. The default "max_input_vars" setting is just 1000 and even for medium size surveys 1000 fields can easily be reached having some multiple choice or array questions.
This can lead to problems when sending updated translation details back to the server and can cause incomplete translations to be stored.

Solution: Check the "max_input_vars" setting on page load and show a warning if the quick translation feature generates too many fields.