Due to some permit hangups, the scheduled construction along the south segment of the trail has been delayed, leaving the entire trail open for several months. From the announcement:

Trail users may enjoy the full East Lake Sammamish Trail for a few more months before the next phase of construction begins. Originally slated to begin construction this fall, final development of the South Sammamish Segment A (from Southeast 43rd Way to Southeast 33rd Street) is temporarily on hold as King County works to ensure the trail meets national safety standards.