When sharing a PDF from Acrobat Reader (free version) on my Android 8 mobile using the "Send a copy" button and choosing Google Drive as my share-to app, by default the Document Title field always begins with "Emailing " and ends with the original PDF filename. For example, a file named myfile.pdf when shared to Drive will by default be given a Document Title (and new filename) of "Emailing myfile.pdf".

My suggestion is simply to make the shared copy's Document Title and filename the same as the original PDF's Document Title and filename.

For the purpose of saving copies of files to storage I believe it would be much better to default to the original title/filename rather than presume all such copies should begin with "Emailing ..." and require the user to always remove the prefixed word or change the entire title/filename every time if they want to maintain a filesystem of concise filenames that can fully benefit from alphabetical sorting.