Your description is a strong match for the refraction of sunlight around the curvature of the Earth due to a combination of clouds and high altitude atmospheric densities. The orange color suggests the sunlight has been shifted from yellow to orange by its passage through the thinner high altitude atmosphere. Red light results in the lower and higher denisty layers of the atmosphere. Slow and rapid changes in position and apprent speeds result from changes in the angle of refraction through the atmospheric layeers, clouds, noctilucent cloud layers, and mirage like reflections. Aircraft navigation lights are sometimes reflected eerily across much greater distances than normal by the same extraordinary atmospheric conditions which refract sunlight and moonlight around the Earth’s curvature.
In somewhat different circumstances, orange ball lightning hovers, bobs, and darts around in the air, around objects, and even through towers and buildings.
Appears it was too late for a refracted sunlight explanation and too low for noctilucent clouds.