However I have an org in our MSP list where I have a HA pair of MX-es that are in NAT mode in a datacenter but the OSPF configuration is available. The tooltip mentions that it is available for MX'es in AutoVPN that are in HUB mode.
Is it correct to assume the feature is available to use or is this some weird dashboard bug?
Oh I didn't know that. Is that written in the documentation somewhere?
So if I follow the logic: The limitation of the OSPF implementation on MX is that they don't support multiple interfaces. Since concentrator mode only has one interface and NAT mode without VLANs basically has one inside interface. So it's not just some weird rule that you had to use concentrator mode for OSPF.
"Note:MX devices in Routed mode only support OSPF on firmware versions 13.4+, with VLANs disabled. OSPF is otherwise supported when the MX is inpassthrough mode on any available firmware version. This can be set underSecurity & SD-WAN > Configure > Addressing & VLANs.
Note: Please note that the MX will only advertise Meraki Auto VPN routes (including static routes shared into Auto VPN) with OSPF. The MX will need static routes configured for any other local subnets."