PDFKit form ignore last user interaction when fill form unless user tap on the done botton

Question

I have an iOS app that allows users to open a PDF form and fill it in. I got a problem when the user edits a text field and then clicks on save without tapping on the "done" button on the keyboard. When saving the PDF the last user entered text will not be committed into the save.

Is there anyway to force the last edit to be committed into the PDF before saving?