I have tried exactly same as you mentioned on Android device and found the same problem.
Yes, when copied the content from the document and pasted it to the text box or google the words are grumbled.
In order to test whether its a problem with the application update or document itself I have tried to reproduce the same with different PDF document and that worked perfectly fine.
So it seems to be a document specific issue. I assume, the fonts used to create the actual document(initial stage) has not been embedded with the file and because of that when you open the file and copy its content its not copying the actual fonts used to create it.
Its not a bug with the application, its a file specific issue.