It appears post 23.1.11 - 23.7 upgrade, all my port forward rules are no longer honoured.
NAT outbound rules seem fine & routing properly. DNS port forward rule doesn't seem to be using the gateway I selected and instead is using the default gateway.
***Quick Update***
Hope this helps someone who may be experiencing the same issue I was.
The issue I had with NAT seemed to present itself post 23.7 upgrade, in particular 'Port Forward'.
Original configuration 23.1.11:
Under NAT / Port Forward, I had a rule specific for DNS (port 53), redirected to a group, i.e. VPN DNS ip's. This group has the ip addresses added pertaining to the VPN's dns servers.
POST 23.7 upgrade, this rule failed & I stumbled across a fix by changing an attribute in the port forward rule.
Current configuration 23.7:
Under NAT / Port Forward, I've now used the specific VLAN interface my host is attached to (instead of the group I had previously) and it seems to work, i.e. my VP provider is showing 'no leaks'.
Strange thing is, under NAT / Outbound, the interface I have listed here is the same group mentioned above that does not work for port forward.
All good now....