Kerbal Space Program

Craft with an engine plate shows zero dV on in-game indicator in certain circumstances, specifically after re-rooting when the engine is in stage 0. This issue shows up in both VAB and with craft active.

This can be seen with a simple construction (craft file attached).

Place descending: Mk2 Lander Can, Rockomax X200-8 Fuel Tank, EP-25 Engine Plate, 48-7S "Spark" Liquid Fuel Engine

Click "Decoupler: Disable Staging" on the Engine Plate

Above the Mk2 Lander, place a Probodobodyne OKTO2, and above that a Clamp-O-Tron Docking Port Jr.

At this point everything appears fine. You should have one stage, stage 0, with the engine and the dV readout.

Re-root the Lander Can to the Docking Port Jr. Pick up the Engine and replace it. The dV readout goes blank.

Click the plus to create a blank stage, or add any other item that is staged, and place it at stage 0, moving the engine to stage 1. The dV readout reappears. Move it back to stage 0, it disappears again.