Same here. For me it appears after loading a game for sure, but cannot roll-out changing ship. Once it actually happen after separation and changing a ship.
The bug seems not modify the size of orbiting circle, but just misplaced it, so it start colliding with Kerbin.
KSP 1.2.0 (vanila)
WIN10 | Intel(R) Core(TM) i7-2600 | NVidia GeForce GTX 980 Ti