https://www.theguardian.com/politics/2024/sep/18/uk-not-for-eu-meat-and-dairy-labelling-postponed
Policy devised under Conservatives will be reviewed after warnings of chaos for producers and suppliers
To avoid tensions and economic issues, the Ireland/Northern Ireland border doesn't have border controls or import duties. However, that means you have to prevent goods that cannot be imported into EU unrestricted from leaving Northern Ireland somehow (otherwise, people will start businesses that systematically circumvent duties). The solution the UK government has chosen here are "not for EU" labels.
But the thing is, those products CAN be imported to the EU just fine. Not without paying and having them checked, but they can.
Of course, with this label, they become basically unsellable in the EU, which is something of a solution I guess?