I'm unsure if this is simply a feature I don't understand or a bug/glitch, but the burn time indicator for the manoeuvre nodes of the spaceship I've assembled by docking sections together in orbit appears red, and only displays "39s". As shown in this screenshot: https://imgur.com/a/bBCGvC9
The engines do work, I did a short test burn to make sure of that. Does anyone know what this is? Any help would be greatly appreciated.