I have a pair of Magnepan MMG, Vandersteen 2 and Mofi Sourcepoint 8 all in my living room, hooked up to the same McIntosh amplifier (using a switch-box).
ALL three pair do the disappearing act . . . but the listening chair had to be moved forward or backward slightly, and the speakers are (obviously) at different positions within the room. It's all about your room (mine is half-treated), the speakers' placement, and the seating position relative to those speakers.
WHY do I have so many different speakers? Each presents the stereo image differently and I switch monitors based on the recording I am playing.