@GazzaGDBB,
26100.2033, is one update behind mine, the problem I described was happening with Build 26100.2152 which is the latest 24H2 update in R.P..
All the other machines on my network are on 23H2.
Sorry, I don't have 26100.2033 anymore, so I cannot check out the same configuration you have.
I may have another PC where I can install 26100.2033 and see what happens. π€·ββοΈ
From your description you don't see any of the other PCs on the network from the one with 26100.2033.
Edit:
I got one machine with Build 26100.2033, sorry I cannot reproduce your problem, I can see all the other PCs on the network from the one with 24H2. (Showing below as K3-PRO-24H2) no problem from any of the other PCs either. π€·ββοΈ
Without seeing your exact configuration settings, I cannot even guess what could be causing your issue. π€·ββοΈ