In addition to the previous discussion of qualification rules, players born in Northern Ireland can play for either team without any parental qualification requirements, as they are innately allowed citizenship of both since the 1998 Belfast Agreement. This has been agreed by FIFA, although the...
MOM last night for Ireland.
https://www.the42.ie/shane-duffy-on-hungary-ireland-5461277-Jun2021/
Problem with inconsistent form is that could be a once-off.