I've been working on this trail for a bit - and while I undertsand the concepts, I'm stumped on why I'm getting this error: 
 

Challenge Not yet complete... here's what's wrong: 
A Create a Record action for the Closed Won criteria node isn't properly configured. Make sure that it creates a draft contract according to the instructions in the ‘Create contract for closed opportunity’ task action. Make sure that Start Date is set by using a formula.

I've gone over all of the workflow tasks information to recreate the contact. If I activate the process and close an opportunity, it creates a contract with the expected information and the date is 1mo away with 12mo term. The workflow's task (which is the template for the actual contract) specifies the following: 
 

Use the closed opportunity to create a contract for the associated account. 

Account: The account associated with this opportunity
Status: Draft
Contract Start Date: 1 month from today
Contract Term: 12

Here are my actions: 


The Contract Start Date is set to the following formula:

DATE(
    YEAR(Today()) +
    FLOOR((1 + MONTH(Today())) / 12) -
    IF (MOD(MONTH(Today()) + 1, 12) = 0,
        1,
        0),

    MOD((1 + MONTH(Today()) - 1), 12) + 1,

    DAY(Today())
)

Again, for all practical purposes I'm passing this, as it functions and the contract is created. But I must be missing some small detail, named field, something that's tripping up the validation settings. Any help is appreciated!