Ligands in search
Searches on words such as 'differentiation' fail in documents where the double f has been formatted as a ligand (the two ff's joined as one symbol). This has been known for thirty years and yet it still happens, it's ridiculous that such a simple feature of text should be able to disable such an important function and advantage of using PDFs to communicate information.
And by the way the hoops you made me jump through to log in, even though I was using correct email and password were just ridiculous -- I simply won't waste my time trying to get to you to improve in future and if I had any say in my company's IT choice I wouldn't use Adobe any more
Rex Parry commented
The security on this website is so complex that it's just not worth using. If you can't find a better way to communicate with your users, you won't get any more help.