5f137dcbe2
This was a regression caused by MDL-30845 or, to be precise, the related issue MDL-32785. Form elements with names like multipier[0] require special handling, such as is present in HTML_QuickForm_element::_prepareValue. I have added equivalent handling to MoodleQuickForm::exportValues. I am afraid that I could not think of a way to do this reliably without duplicating code.