Again, I disagree. Accounts receivable is first $500,000 based on what I'm reading in the accounting rules.
I did miss the deferred revenue line item for $1 million. That would be both $500,000 payments. One has been received, but can't be booked as revenue per the accounting rules (link I provided), thus accounts receivable equals $500,000. The other hasn't been received, but has been booked in deferred revenue.
Together, both are deferred revenue at the moment.