Reproduce:
Have Precise Maneuver plugin installed.
Place a few maneuver nodes and confirm there are no errors.
In orbit, run Orbital Autopilot -> Land.
Abort the command, delete the node.
Place a maneuver node again manually, Precise Maneuver won't come up, and it throws an error:
[EXC 07:27:18.486] NullReferenceException: Object reference not set to an instance of an object
KSPPreciseManeuver.NodeTools.GetTargetOrbit (.CelestialBody refbody)
KSPPreciseManeuver.NodeManager.UpdateNodes ()
KSPPreciseManeuver.PreciseManeuver.Update ()
Ref: https://github.com/allista/ThrottleControlledAvionics/issues/64
Reproduce: Have Precise Maneuver plugin installed. Place a few maneuver nodes and confirm there are no errors. In orbit, run Orbital Autopilot -> Land. Abort the command, delete the node. Place a maneuver node again manually, Precise Maneuver won't come up, and it throws an error: