[sfplay~] cue list weirdness

Hi all,
My friend is making a patch which plays a fixed media part along with a click track from two separate AIFF files of the same length (with two different [sfplay~] objects). Each rehearsal mark in the score corresponds to a preloaded cue loadbanged into both [sfplay~] objects and the conductor can select a rehearsal mark from a [umenu] which triggers that cue. Strangely, some cues trigger a little less than a second too early in both files (despite checking and double-checking that the ms value for that preload message is correct). It's only for about 4 cues out of 15, and there doesn't seem to be any pattern in the desired times. Sending "seek" with the same ms value to both objects yields the same results, as did trying it on two machines.
Anyone experienced glitchy behavior like this with [sfplay~] cue lists?