Additional testing suggests you are right, with a clean 24.2 install with only MJ, MM and your mod it worked fine. Some other weird issues i had was also nonexistent. Aside from the few missing tweakables, the CoM marker, prices, mass and thrust values get NaN displayed. I traced the problem to the radial Zenith booster, as it has many yellow warning, followed by a NullReferenceException in the debug log upon loading the prebuilt craft files. Here is the log file for the errors http://s000.tinyupload.com/index.php?file_id=00008260453547344017