This is completely normal, I believe it just has to do with how SRB2 stores objects and the interpolation. When an object disappears, it isn't actually destroyed, it's instead put into a low part of the map that's out of the player's vision. Because interpolation is basically just moving an object from one place to another with more frames, Uncapped sees the transition from "existing" to "not existing" and counts it as motion, thus you see the object in the wrong spot.
But actually, I have no idea what I'm talking about, so take this with a grain of salt.