"The value all must be false when items are provided."

I am receiving the following error message when attempting to create a discount on a specific Collection (by ID):

[{“message”:“The value all must be false when items are provided.”,“locations”:[{“line”:3,“column”:3}],“path”:[“discountCodeBasicCreate”]}]

This code creates the Discount correctly when applying to all Items but not when applying to a Collection.

You can see from this code sample that I have “all” to set to “false”:

I can’t imagine what else it mentions should be false that would be relevant.

Perhaps just another in a long list of broken dreams with this API…