Ideas are a custom content type. That code is separate from the core code so it could be that it is simply a bug you have discovered. You may have to work through support in order to verify that the activity is not there so that they can log it as a something to fix.
Thanks Kevin. I will do a bit more investigating before going back to Support or perhaps Prof.Services.
Looking at my installation, we are collecting activities for IDEAS.
We are on 7.0.2, but I also have data from before upgrading to this version.
The query I did was:-
join jivedw_object on direct_dw_object_id = dw_object_id
where direct_object_type = 3227383
Thanks Jeremy, this looks useful. Will certainly test this query.