Having a strange issue with a form i'm working on at the moment. My datasource is a SharePoint list. Right now, I'm working with just one field ("Line Manager") which is a person field. On my form I have set the datacard's default value to the following:
If(FormCreateNewRequest.Mode = New, Office365Users.Manager(Office365Users.MyProfile().Mail), ThisItem.Line_x0020_Manager)
When I navigate to the form and submit it using the SubmitForm method, I receive the error below. I've set the SharePoint list to have no required fields, but the error persists. However, if I change the value of this field (i.e. Type the name of someone else and select them) the form will submit succesfully.

I have tried to work around this bug by instead getting the value of this field and then patching the record manually:
Patch('IT Equipment Requests', Defaults('IT Equipment Requests'),
{
Line_x0020_Manager: DataCardLineManagerInput.Selected
}
)Unfortunately this won't work as the following error is detected in the Patch function:

Soo my question now is, how do i correctly emulate setting a "Person" field using Patch, or is there something I'm doing wrong with setting the Default property of that field?