Version used: Mp3tag v2.23k
When rewriting an ogg tag with special tag information, some information is lost during the saving.
As you know, OGG tags lets you specify any name for a tag and assign a value for it. For example, i have files with a "DAE" tag containing the value "EAC v0.95 prebeta 5" and a "Encoder" tag containing the value "OggEnc v1.0.1 VBR Quality=6". When saving tags with Mp3tag (for example, to batch-change the genre), the information including and after the "=" character is lost.
So, in my example, the tag "Encoder" has an original value of "OggEnc v1.0.1 VBR Quality=6" and after saving it with Mp3tag, the value becomes "OggEnc v1.0.1 VBR Quality".
It seems like a bug, but i'm no expert...