They are uncomfortable in the situation. If members feel uncomfortable, it may be because they don't know what is expected of them or how to participate in the group's activity. By misbehaving, the members don't have to figure out what is expected. A few quiet words to explain what to do will probably solve the problem. They are afraid of failure.
Fear of failure can also make members feel uncomfortable.
It may be less embarrassing to be called a troublemaker than to be called a failure . Try to promote a team spirit in the group where no one ridicules a person who goofs. Also, be sure that everyone knows how to perform his or her role or assignment. They don't like or aren't interested in what the group is doing. There could be several reasons for this.