First delve into the Meraki side of things and ...........
I have a MX64, 120 switch and MR 36.
MX64 is the DHCP server with 3 vlans configured (2,3,4). DHCP is set for vlan 3 and 4, with vlan 2 the Management VLAN.
MX64 is trunked to the Switch, all vlans allowed.
Switch is then trunked to the MR36.
On all trunks the native vlan is set to vlan 2.
When i setup the AP i set it to DHCP on vlan 4 and the trunk from switch 2 was set to native vlan 4 to do this.
When i push the change to AP to static IP on vlan 2, i can see it pushes the change and see the IP in the portal.
However the native vlan is on the switch is vlan 4. When i change that to vlan 2, the AP then reverts its config back to getting an IP on vlan 4 dynamically, like the initial setup.
Scratching my head at the logic, and why this happens.