diff --git a/manager/scheduler/scheduler.go b/manager/scheduler/scheduler.go
index 55420a2d42..e79c0f0532 100644
--- a/manager/scheduler/scheduler.go
+++ b/manager/scheduler/scheduler.go
@@ -602,6 +602,12 @@ func (s *Scheduler) scheduleNTasksOnNodes(ctx context.Context, n int, taskGroup
 	nodeIter := 0
 	nodeCount := len(nodes)
 	for taskID, t := range taskGroup {
+		// Skip tasks which were already scheduled because they ended
+		// up in two groups at once.
+		if _, exists := schedulingDecisions[taskID]; exists {
+			continue
+		}
+
 		node := &nodes[nodeIter%nodeCount]
 
 		log.G(ctx).WithField("task.id", t.ID).Debugf("assigning to node %s", node.ID)