Ok, I open Safari and click the button on the bottom right, circled in yellow:
I then see my old device noted, again circled in yellow, instead of my current iPhone X:
I checked Settings > General > About and the name there is correct - iPhone X.
Where is it getting that 8 Plus?

I then see my old device noted, again circled in yellow, instead of my current iPhone X:

I checked Settings > General > About and the name there is correct - iPhone X.
Where is it getting that 8 Plus?