When attempting to modify the MTU value of an interface:

PUT /restconf/config/ietf-interfaces:interfaces
{
"name": "GigabitEthernet0/8/0",
"v3po:ethernet":

,
...
}
returns code 200: OK and updates config data, but operational data and VAT interface dump still show the default value of 9216.

Performing the same operation through VPP console:
"set interface mtu 1500 GigabitEthernet0/8/0"
works as expected.

This appears to be a missing writer issue, however the log contains no "missing writer" entries.