Not sure whether its a bug or not.
I have created a set of actions to split the entries I got from Discogs into multiple entries. I use it mainly for artists, composers and mainly genres. From discogs i get them comma separated. The delimiter at mp3Tag is the double backslash to seperate the entries. But when use a regex replace action its saved including the delimiter. Let me show a screenshot. This is the result after the regex replace action.
The tag is saved including the double backslash instead of two genre entries. After saving it again via Strg+S it is split into two entries. The most strange thing is. The resave does work only with one or a few selected files. Mark all (Strg+A followed by Strg+S) does not work - maybe because the tag contains mixed entries and shows "keep entry". So, If I want to split the entries of many albums I can use my replace action but have to save the single files (or at least every album) separately.