Suggested Genres - append to existing & re-route to different field features ?

[alec.tron]

Hello,
a few questions regarding the suggested Genres functionality as I can't find a documentation for this, bar a few threads, so a context questions:
- I assume if this is spotify API then it's Album based genres (not track or artist based ones) ? So one would add them ideally on a per-album basis...?

And for specific features:
- if I apply the incoming values to a genre field that already holds data, the new values aren't appended, but they overwrite/remove all previous genre tags. Is there a way to set this to always 'append' and not overwrite/remove existing ones ?
- also, as is, it seems to only write to the default genre field (or is there ways to re-route to other/custom fields ? i.e. 'genre_spotify' if I were to set up a field for that...?)

And an oddity for workflow/UI (I'd consider a bug, probably ?):
- selecting multiples of the incoming suggested genres only works with Ctrl-click, but it does not mark the currently clicked with a tick, but only the previously selected & then deselected one, not the one that was actually clicked.. anyone else seeing this ?

Cheers.
c.