OA_GROUP_FIELD does not exist on most (any?) content, use OG_AUDIENCE_FIELD

We use the flag  "subscribe_section_content" automatically for users joining a space. This does not send out emails on content created in the space.

During debugging I see the code trying to access OA_GROUP_FIELD on the new content, which translates to "field_oa_group_ref", which does not exist on regular content. Maybe on sections?

As far as I can tell, the correct CONST here is OG_AUDIENCE_FIELD which does what I expect it to do.

So I guess this is actually a bug.