Autoburn says Current Stage Incapable of Producing Thrust when engines are not active

(BETA) Water Nuclear engine isnt recognised by burn nodes, no burn time displayed in Orbit window and error message "Current Stage Incapable of Producing Thrust" shown while auto-warping. AutoBurn occurs as normal despite this message, however.

Engine is fully controllable with throttle and shown as active.

Craft is command capsule, tank, nuclear engine and intake "fairing" around engine base.

EDIT: Stage burn-time and dV are also missing in map view.