So, two examples where the provenance of the inheritance are extremely relevant, there may be more examples
USA - if an Irish resident inherits from a US resident, the USA taxes the inheritance as full and final liability. Even if the tax paid in the USA is nil due to the exceptionally large exemption.
UK - if one takes an inheritance from the UK it is possible to vary the UK Will (say to a trust) within two years of death provided all the beneficiaries of the will are over the age of majority and in agreement to the variation.
That would prevent the inheritance hitting in Ireland and potentially avoid Irish CAT.