Loading existing mp3 tags

I am new to the use of MP3TAG and want to use it to organize the current tags I have in my music collection. I have the strange situation however that I am not seeing the MP3 Tags while they are there. I am using a Sonos audio system and noticed that on some of the MP3 music more information was available then I saw in MP3 Tag I checked things and noticed that in MP3 Bookhelper and Tag&Rename the information came up.

I was using the latest official release V2.36a and deinstalled and went for V2.36d instead and then I saw the Tag information again. Problem solved I thought but this was not for long. After changing the options in Mp3Tag I again could not see the tags. I deinstalled again and installed it again and changed less in the tools / option menu and now it seems to work still. Am I doing something wrong here or is this a known issue / bug. Note that when I cannot see the tags I am still able to see the majority of other tags.

Maybe your audio system does not support unicode or ID3v2.4 tags. Try writing unicode ID3v2.3 tags instead. If that doesn't work, switch to ISO.

No the problem was the other way around my Sonos system was seeing the tags but the MP3TAG software wasn't. Doing a new install and not changing everything in once in the tool / options menu seems to keep the tags usable. Doesn't sound to logical to me but now is it working and I try not to change anything in the settings.