this has been happening for a few weeks.
i work with a lot of extruded crvs mostly made of planar surfaces. on of my scripts prompts you to select a planar surface to set the cplane to. if it’s not planar it alerts you.
you can see in the grab that when that surface is part of a solid it’s not planar, extracted it’s planar, solid exploded it’s planar. this happens to me fairly regularly.