When reading a PDF attachment in the Zotero iOS app, I can add only *one* PDF comment. After I write this comment, I am unable to edit it again. (Tapping on the comment selects it, but no edit box opens.) If I try to add new comments, it creates a comment icon, but similarly it cannot be edited. Even if I open a new PDF, I cannot add even a single comment.

When I restart the app, I can edit/add exactly one comment again, then the issue returns.