We ended up creating a "dummy" child for every parent.
Same bug gives issues on the copy action. Making the parent list a production list is the only workaround, but if this is not possible (anymore) there is no workaround available currently.
Latest reply from support: "Development Team does have intention to fix this issue in the future release however the timeline is not announced "
I was just wondering if there is any update on this? We are having this same issue. Of note, we are able to manually add to the production list out in our Prod workspace, but the action still is not working to create on the list.
You might want to the support route on this as I thought it was fixed a while back.
Thanks Rob! Will do. Appreciate the reply.