Confused Hub2?

[#1]

I've noted a slight 'discrepancy' on my Hub2

The configuration is (Advanced settings, IPv4 configuration)

Yet the router shows (in 'Status')

[#2]

That's a 'feature' - it will always show then PN DNS servers in that order regardless of what you have set in advanced.
I use NextDNS and still see the PN ones.

[#3]

This isn't a discrepancy, it's an accurate reflection of what's happening.
The addresses under 'status' are those assigned to the hub's WAN/PPPoE interface and will always be those that are auto assigned by the broadband network.
The custom DNS addresses are assigned to connecting devices as part of their DHCP lease. This results in clients going direct to your DNS server of choice, rather than relying on the DNS assigned to the hub's broadband connection (which will still be configured to use Plusnet).

[#4]

"The custom DNS addresses are assigned to connecting devices as part of their DHCP lease. This results in clients going direct to your DNS server of choice, rather than relying on the DNS assigned to the hub's broadband connection (which will still be configured to use Plusnet)."

Yes.

"The addresses under 'status' are those assigned to the hub's WAN/PPPoE interface and will always be those that are auto assigned by the broadband network."

How are they assigned?

Currently the 'assigned' are...

Secondary question. Are the DNS addresses assigned by the Hub's WAN/PPPoE interface to the Hub based on stored information previously retrieved from the Hub which may become 'inverted'? I note that my local Hub2 config is not factory standard (the s/w is, though)

[#5]

That may be the case, but I've switched some stuff around to verify (moved my config to use the secondary DNS servers in the pairs - just checking). However, I have noted that the primary and secondary DNS servers on the Hub's status page are liable to switch around (see update posted a little bit earlier), and therefore not always in that order.