Although this workaround is clunky, I have used it when I ran across the same problem; you must have Acrobat Pro, however, as the simple reader won’t have the features I am about to describe (though perhaps there are similar workarounds using other software).
STEP 1: In Acrobat Pro, “Export” the errant file as an image file (I used PNG for mine) via “File > Export > Image > PNG”; one caveat here is that Acrobat will create a unique image file for each page of your original document.
STEP 2: From Acrobat select “File > Open” and be sure to select “All files” from the “Files of type:” dropdown, otherwise you will not see your PNG file. Navigate to whatever image file you need (i.e. whatever page you need to copy/paste from; you’ll have to do these one at a time, or open them all at the same time and “combine” them if you need access to most or all pages) ... and open the file(s) you need.
STEP 3: From your opened “image” file in Acrobat select “Document > OCR Text Recognition > Recognize text using OCR… ” and let Acrobat do the work.
STEP 4: Now you can copy and paste the text, though you might need to do some editing of the result, so check you work carefully.
If anyone knows of a better method, please do share!