I have clients experiencing a delay when the refund includes RRC for a child born in  2020.

EDIT:    I'm assuming the delay is because of the RRC for child born in 2020. 

"when the refund includes RRC for a child born in  2020."

I thought that was only your speculative reason, and you never proved it. However, your topic did result in others mentioning the RRC reconciliation (amount eligible for vs amount already paid) was a problem.

Those are two different reasons for an EIP-related delay.

I've edited my response to indicate my answer is just my assumption.