When I’am trying to copy a text from a PDF-file on macOS containing the character ἀ (ancient Greek alpha with spiritus lenis), all characters are copied without any problem, but all ἀ aren’t copied.
My guess is they were added as graphic elements, not real characters, probably due to a font encoding issue.
Can you share with us a sample file that demonstrates this issue?
Works fine for me:
Yes, because you are using Adobe Acrobat/Reader for Windows and not for macOS. The problem occurs only on macOS.
I don't think that should matter, but yes, I'm doing it on a Windows machine. I can't test it on a Mac.