Change Plan's Owner/Group - Required Permissions missing - microsoft-graph-api

Question

When attempting to update a Planner Plan's group using PATCH, updates to the owner field fail with 403. The attempt is being made using the Graph Explorer (and also fails using PostMan).
An attempt to change the title field succeeds (no issue with permissions, using eTag, etc.) for the call.
The documentation indicate Groups.ReadWrite.All are required, and that the owner can only be changed by the Group Owner, but the account being used is the owner of the unified group.
Are there any additional permissions required?
Example info:
If-Match: W/"JzEtUGxhbiAgQEBAQEBAQEBAQEBAQEBARCc="
PATCH https://graph.microsoft.com/beta/planner/plans/Vk_27olfLESU6vWJNgzVT2UABrBj
BODY:
{
"title": "Updated plan with new group owner",
"owner": "0ab4b389-7c7c-4757-ac75-2ba5de8c8197"
}
RESPONSE:
{
"error": {
"code": "",
"message": "You do not have the required permissions to access this item, or the item may not exist.",
"innerError": {
"request-id": "7696b78c-474f-4fc0-bba9-4554bfe303c4",
"date": "2018-11-14T16:50:59"
}
}
}

Answer 1

The documentation in this case is misleading/incorrect (it is trying to say the field owner can only be updated by the principal identified by the value of the owner field, which is a group that cannot actually perform operations, not the owner of that group). We'll update the documentation and clarify.
We currently do not allow Plans to be moved between groups, as some of the related items mostly live within the group itself (e.g. membership, comments, document links). We'd like to understand your scenario better to see if we could support it, so please provide feedback on https://planner.uservoice.com.