We are using Adobe 2020.013.20066 and all our team experience the same bug. When entering a text block using Fill & Sign; the entered text not only appears on the page where it was originally entered but it then 'appears' on random page throughout the document.

Attached example shows screenshots from a document pasted into a word file.

More examples on the Adobe's forum: https://community.adobe.com/t5/acrobat-reader/bug-in-adobe-reader-when-entering-text-field/m-p/11647598?page=1#M73751

This bug surely needs to be fixed.