Cannot change the Epic of a next - gen issue

I was told that any bugs related to Jira Cloud should be posted here, rather than creating a ticket on DEVHELP…

Anyhow here it is:

According to the documentation of the Jira Cloud REST API, apps and users can use the edit issue endpoint to change the parent of an issue.

quoting the docs:
"The parent field may be set by key or ID. For standard issue types, the parent may be removed by setting update.parent.set.none to true. "

Now, on a next gen issue setting a parent works well, but assigning to none via this path does not work. Instead Jira replies with

“parent”: “Field ‘parent’ cannot be set. It is not on the appropriate screen, or unknown.”

How are we supposed to unassign an issue from an Epic?