In the file /mod/community/lib/community_member_add.php, line 29, there is an erroneous check for email notifications. The code within this check is only executed if the person has email notification turned on.
In fact, this code should always get executed. Because of this error, community owners only receive notification of new memners if they have emial notification turned on, and even more importantly, a "community:member" publish event is triggered only if the owner of the community happens to have email notification turned on.
To fix this problem, comment out or remove the begiining of the if (line 29) and the end of the if (line 34).
