I'm glad you've got the problem licked now, or at least understand the limitations on some of your downloaded PDF documents. I suspect those limitations will apply to all documents that are downloaded from the same database or source, and will consistently
not apply to documents downloaded from specific other databases, because of differences in the way documents are scanned by different database services.
By way of clarification, let me just point out that what you are calling Acrobat, which used to be called *Acrobat Reader,* is now officially called *Adobe Reader.* Adobe changed the name to distinguish more clearly between
Acrobat — an expensive commercial application for +creating, modifying and manipulating+ PDF files — and the freeware Adobe Reader, which only enables you to
view them. You'll avoid needless confusion by calling the Reader by its proper name in the future. No big deal, though: lots of people make the same mistake here. (I've explained this distinction to my wife any number of times, and have finally learned not to bother doing it again: she simply doesn't care.) 😉