Temporary resolution in 2.5.12: We skip the field and display an error message at the top of the form. The form works well without it.
It uses Chrome + RY 2.5.11.
I was able to pinpoint the precise issue and fixed it. No JS error now, and if there were an error message, the form would still work.
Ok, it is strange because .renderFields() doesn't call any .value() method on any object.
Added a try/catch, so at least they can bypass this field.