Use REST API to load Element Entry but getting errors we don't experience through the UI

Summary:

We have a nonrecurring deduction element for lost badge fee that I am using for proof of concept with the delivered REST API

Content (please ensure you mask any confidential information):

I have added 'API' to the PAY_CREATOR_TYPE lookup and am having mixed results. In some cases, I can add the element entry once but not a second time. In other cases, I cannot even add the element entry once. I suspect there is configuration that I'm not aware of that prevents me in a few of the use cases, so for starters I am only asking about this specific message: