Bucket assignment is dropping when you edit a task on an iOS Planner App.
Bucket Assignment is dropping from tasks after you edit a task using the current version (1.8.17) of the iOS Planner App on both iPad and iPhone. It only happens on other devices, not the device you edit it on. For example, edit a task on the ipad app and the bucket assignment drops from the task on iphone and web versions of planner, you no longer see the task in group by Bucket view. You have to use another view to find the task and you can assign a bucket again.
