SNAT on RED fails silently with DHCP

I was playing around with some routed networks and in order to allow one of them access to the internet, I added a static route to its gateway and added a source nat rule for that network.

Like this:

I was surprised to find that the packets where leaving on RED with as a source. This is what I found in IpTables:

So I manually changed it and then it worked fine.

So then I changed RED from DHCP to STATIC and that was better:

It makes sense that it did not work the first time, when RED was set to DHCP. A MASQUERADE would have been required. But it is misleading that the NAT rule shows the new source IP address as RED ( That suggest that it will indeed be, not

So maybe RED should not be available for NAT if it is set to DHCP? Or better yet, it should add a MASQUERADE instead of SNAT?

OR DHCP reservation?