I like the way the “Things” app handles the repeating tasks.
It has one “Master Copy” of each repeating item which is editable; but not completable. It is indicated by a repeat icon at the start of the item and either the date the item will next generate the new task or says “waiting” to indicate that the previous instance of the task has not yet been checked off.
Edits to that “Master Copy” will perpetuate to all future instances.
When the new task is generated, it becomes a stand alone task with no link to the “Master copy” (other than the text being the same of course) - you can add notes, make changes to THAT INSTANCE, even move it to a different location and it will be checked off as an individual task, remain in the completed view, etc.
I would love to see that in Legend.