The course owner can add and remove participants in date enrollment. When done, he has the possibility to send an email to the added or removed participant. The subject (and also a part of the body) of this email is always the subject of the first date in datelist (dateList.get(0).getSubject()). The correct subject should be the subject where the participant is enrolled or removed.
Furthermore when selecting multiple dates in the participant table for removing the participants, the subject of the mail is also the subject of the first date. My suggestion is to set the short title of the course node as subject.
This is the patch: