Just a heads up for Form 2441.  At the top of the 2441 input is a question B-related to taxpayer(s) having a principal place of residence in the US.  The child credit can be refundable if this box is checked 'yes'.

Checking this box may move the credit from line 20 of Form 1040 to line 31 Form 1040-(Sch 3)

Not sure if an amendment is needed since the refund does not change.