An update on this issue: after further investigation we have identified a bug which affects text in the Description field when creating a criterion in a form. If the text is copied and pasted from another source (e.g. Word or Outlook) and contains any special characters (e.g. quotation marks, bullet points and other punctuation marks) the criterion breaks the form. It's still possible to view broken forms and open them for editing, but any criteria that had been added before the form broke are no longer visible, adding a new criterion throws the error reported in my earlier message, and it is not possible to delete the form.
The issue can be worked around by avoiding special characters in the Description field, but we would like to find a fix if possible. Has anyone encountered this issue and is there a fix we can apply?
Thank you in advance