Comment by Aloisius

The UK versions all seem to have calcium phosphate in them too.

https://www.britishcornershop.co.uk/quaker-oat-so-simple-hea...

https://www.sainsburys.co.uk/gol-ui/product/quaker-oats-high...

For some reason, the quaker oats uk website doesn't list it though, perhaps they're new formulations.

I imagine it's used to keep the fine powders (powdered salt or milk powder depending on the product) from caking. If the previous version didn't have any salt, then it might not have needed it.