Missing Workouts

Up until the end of last week, I enjoyed doing a particular group workout - 3 by 13 minute climbs. It now no longer features in the schedule of group workouts, and more annoyingly I can’t find it anywhere in the Workouts on Zwift or on WhatsOnZwift.
Is this normal procedure, for workouts to be removed, not only from the schedule but also from he available workouts, and is there any rhyme or reason to this, or can I just expect workouts to appear and disappear at random?
Many thanks