IIRC, this was mooted about at the time, and the RC-135 was supposed to have turned back long before KAL flight was intercepted. Also, and again this is a really dim memory, at the time I looked at the reported tracks of the two and decided they could not have come closer to one another on a GCI scope than several inches, which doesn't seem too confusing.
Of course, everyone involved could have been lying from day one, so I doubt we'll ever know.