Issue related to WPMU on multi-db


We are running WPMU on multi-db,
its noticed that plugins(both from premium and others) that create tables goes into the DB named "..._wpmud4".

Is this normal or should it go into the "..._wpmuglobal" DB?

Also, our error_log is getting loaded with table does not exist entries: eg: tables are "wp_user_activity", "wp_tips" etc. << these tables does exists on the "..._wpmuglobal" database.....I guess its looking for those tables in the "..._wpmud4" DB?

Is there anything we missed or have done anything wrong while multi-db was installed. ?

Look forward to your thoughts.

Thanks & Regards