When I open any acrobat document, the cursor "blinking on the document is very large covering about ten to fifteen lines of text.
Could you send the PDF? You can upload the files at https://cloud.acrobat.com/send and paste the link here.
Gil Man Thapa commented
I think you saved that pdf file form website so it happened. pl try this one.
Control + P (in website page)
Print page will open then destination section
Select save as pdf
Click on save
and save where you like.
Other way is
Press Control + P on that file and save it with different name. Thats it. Thank you.