What I believe happens here is that original FILM is shot @ 24fps. NTSC TVs display @ 59.94 FIELDS per second, technically 29.97 "frames per second". Do to electronics mumbo jumbo the NTSC standard is %1 slower then 30FRAMES PER SECOND. So what they do is they take the 24fps video, slow it down %1 and then do telecining, which is the process of meshing together fields to produce whole frames to increase the frame rate from to 29.97 frames per second.
So if you import 23.976 / 23.98fps video into Premiere, but you have a 24fps timeline then you're going to have some slight timing issues

. The cure I guess is to speed up teh video and audio by %1 and then edit it in Premiere. Then you can slow it back down

Or you can just leave it be and see if it causes much of a problem :\
~klinky