I got a bug report. Sadly i can't see a good solution without getting other (bigger) disadvantages.
If you get wrong characters while importing a CSV file, please save the CSV file with UTF8 encoding.
So if you use LibreOffice calc, please "save as", selecte "csv" fileformat, check the "Edit Filter Settings" checkbox and select "UTF8" character set.
You can also change the encoding in Excel. (I currently can't write the exact way, since i haven't got Excel at home. But it is pretty similar to LibreOffice).
If you use an editor to write your csv file, please use an "professional" one. Not an "easy" one. Several "small" editors doesn't allow to change the encoding.
If you can't change the character set in your editor i suggest a very professional editor like "notepad++". You can save as UTF8 with that editor. see https://notepad-plus-plus.org/