Rapidly fluctuating values of Ascending / Descending node

[scimas]

I have a ship in transfer orbit from Kerbin to Minmus. In the Minmus-Kerbin barycentric frame, the T- and out of plane speed values of the first ascending and descending node can be seen fluctuating rapidly over a range of 10 min and ~5 m/s. The third node (ascending) isn't fluctuating in short term, but if observed for about 2 min, its out of plane speed can also be seen to change by 1 m/s.
Ship in question RDD 3.
Mods: Principia, ScanSat, RemoteTech, Ven's Stock Revamp, Transfer Window Planner, KAC, KER, x Science, FAR, kOS, LaserDist, ManeuverQueue, RCS Build Aid, Module Manager, Modular Flight Integrator.
bug.zip