I found the "Character encoding" setting in Preferences->ID3 Tags->ID3v2 (dconf entry: /org/gnome/easytag/id3v2-enable-unicode) seems to be completely ignored when EasyTAG is set to use ID3v2.4. No matter I choose Unicode or Other, the Other encoding (id3v2-no-unicode-charset) is always used.

For example, when id3v2-no-unicode-charset is the default 'iso-8859-1', EasyTAG will always try to encode tags in ASCII, even if I choose Unicode for ID3v2. I can see convert_string error messages in the log window, complaining unable to encode the non-ASCII characters to iso-8859-1. And the resultant file has ID3 tags encoded in ASCII. On the other hand, if I set id3v2-no-unicode-charset to UTF-8, then EasyTAG will write tags in UTF-8 correctly.

In a word, it seems the id3v2-enable-unicode setting is ignored and the encoding is always determined by id3v2-no-unicode-charset.

FYI, I'm using EasyTAG 3.4.0 (Archlinux). ID3v1 disabled and I'm using ID3v2.4. Other settings are all the default. I also tried selecting ID3v2.3 in EasyTAG, which worked as expected (tags were encoded in UTF-16 or the one specified in Otherg, depending on the enable-unicode option).

Note: I verify the encoding of ID3v2 tags by using "mid3v2 --list-raw" (a tool from mutagen), especially looking at the encoding value of each frame (UTF-8 has encoding=3, while iso-8859-1 has encoding=0).