EIP#3 for independent child

Per a fairly well-known tax seminar that I attended last month, if a child was claimed on the parents' 2020 Form 1040 but became independent 2021, there is an EIP problem. If the parents received the advance EIP#3 of $4,200 (based on husband, wife and dependent child), and the child becomes independent in 2021 and claims himself, the child is not eligible for the EIP#3 on his Form 1040. Has anyone heard of this? And if this is accurate, will divorced parent who claimed child in 2020 and received the advance EIP#3 but does not claim the child in 2021 have to pay back the $1,400?

EIP 3 was an advance to be reconciled against actual allowable amount on 2021 1040.
I don't think any EIP3 has to be repaid.

Independent, former dependent, child claims the credit to which they are entitled on their 2021 1040.