I created a form in Adobe Acrobat DC using Prepare Form and sent them out. Most of them were filled in fine (by respondents using Acrobat Reader) but one user returned the form as a flat non-editable PDF with mistakes in her entries (spelling, grammar) that I need to fix. I reopened the pdf using Acrobat DC Prepare Form and all the fields are showing up fine. HOWEVER when I try to edit the text to make corrections I find that I can only delete her text; I cant add in any new text.
I've checked the properties and the fields are not locked or set to read only. The security settings allow editing. What the hell has happened?