When setting up BigBlueButton activity in a course and checking the setting to open the activity in a new window, Moodle seems to be stripping the 'target="_blank"' from the URL string.

To recreate the issue, create a new BigBlueButton activity in a course and choose to open the activity in a new window. Save and go to the activity and Moodle will open the connection to the BBB server in the same window.