Hi @ConfusedAnt, first of all, welcome to the community!
I’m so sorry to hear you’re having trouble with the due date. When quickly testing this myself, I could reproduce the problem. From taking a (very) quick look into this it seems we are sending a dueDate field whereas the expected field would be due.
I’ll test this later today and will propose a fix if confirmed.
Turns out it was indeed the wrong field name causing this. Once this is changed to due, setting the date works. I’ve raised a PR with the fix and will let you know once this has been released.