Copying text from a PDF and pasting to TextEdit etc. missing certain characters

Hello, a strange issue with Acrobat DC (latest version). Im running iMac 2019 / Big Sur 11.4.

When I open any PDF document with Acrobat and copy/paste text from the pdf to TextEdit (in Plain Text mode), the copied text is missing all ä, ö and å characters, which are very common in Finnish language.

The problem started this morning. Earlier last week I copy/paste'd 150 pages of text full of ä's and ö's without any problems. 

In "Plain text mode" (which I use to get rid of formatting) TextEdit replaces ä, ö and å characters in the copied text with empty spaces. So for example copying a word like "Säätila" from a pdf in Acrobat, reads "S tila" in TextEdit. 

I also tested copying and pasting text from a PDF (opened in Acrobat) directly to Illustrator, Photoshop, inDesign and Google Chromes address bar, and the same problem is there. Ä's and ö's and other Scandinavian characters are missing.

Copying text with Acrobats "Copy with formatting"-option (which Ive never used before) also works but then the text has unnecessary hyphens, so that doesn't really help me. Only cases where copy/paste works (at least for me) is when copying from Acrobat to TextEdits "Rich Text mode", gmails new message or Macs own programs like "Pages".

After I noticed the problem, I made the latest Big Sur update, uninstalled/reinstalled Acrobat DC twice, but the problem is still there.

So after everything I've tested, the root of the problem seems to be when copying text from a PDF in Acrobat DC. Elsewhere copy/paste seems to work fine.

Any idea what's causing this?