Text is Replaced Temporarily when Highlighting Text

[Lucas31734012yd0y]

For some reason, whenever I highlight text, Acrobat temporarily blocks out the text I'm working on and covers it up with other (seemingly random) text.  The random text dissapears as soon as I'm finished highlighting, but it makes it difficult to highlight multiple lines because the size of the cover text is much larger than the base text.  

I've ran the repair tool and the OCR tool with no success.  This also happens on pretty much every document I have. I know this is confusing so I included a few screenshots. The first image is without any attempt at highlighting. The second shows what my text looks like after I attempt highlighting. 

Any help would be appreciated! 

[try67]

It seems to have overlapping text streams. The issue is most likely with how the file was created. 

Did you create it yourself? If so, how?

Can you share a sample file?

[Lucas31734012yd0y]

I did make this file and the other files I have been using myself. Most have either been converted from a word document or a powerpoint to this PDF.  Heres the file that I'm currently using. For this file, I imported the powerpoint slides into acrobat and converted them within Adobe's software. Thanks for the quick reply!

[try67]

So I don't have to search a 645-page file, on what exact page does this happen?

[Lucas31734012yd0y]

I supposed I should have clarified, this happens on basically all of the pages. I just included that to not change any of the variables.