Pretty sure I was using 1.43. This is completely incompatible with Infernal Robotics, any IR part on my ship causes what would appear to be the ship losing its root node. My ship is destroyed, and if I manage to get it to the launch pad, the save is irrevocably damaged as well. Upgrading to 1.47 "seemed" to fix the IR issues. However, weirdness as well happens. RCS parts on pre-built ships are much larger, probably scaled to the largest setting. I only noticed this on the stock rcs thrusters and the smaller circular side mount tanks, because those were the only RCS parts I had unlocked. Attaching new RCS parts in the VAB worked as expected. In the SPH, when building a space plane, I was not able to attach any air intakes in mirror mode. I could hack an attach by going in singular mode and then grabbing a new part and attaching in the same place on the other side of the vehicle. However, upon launch, the vehicle was destroyed and on loading the auto save, the ship seemed to have lost its root node like from the original IR issue. Whenever attaching to a decoupler a part will resize to whatever diameter the decoupler is. TLDR: RCS, Air Intakes, and decouplers might be a productive avenue of research. I can provide screenshots, but the descriptions should be pretty self-explanatory. Logs too, if wanted. Cheers