I understand if the pre-comp has been nudged in the composition that it is nested in, this phenomenon will occur when trying to lineup a keyframe within a pre-comp for example to a frame outside the pre-comp. But I've made sure this particular pre-comp is snapped at 0 in its parent comp, and it is -- not to mention, everything functionally lines up (i.e. a keyframe located at 700 in the pre-comp performs its action at frame 700 outside the pre-comp as well). But when I snap the playhead to that keyframe in the pre-comp for example, and then navigate out to the main composition it is nested in, now the playhead is at 699. Hmm!
Most likely, I'm missing some obvious After Effects mode of thought, but I'm just confused why my playhead keeps moving to different frame numbers when my pre-comps are all flush with the main composition timeline not to mention everything is visually lining up as it should.
check these 2 things:
1. that the frame rate of you master comp and your precomp is the same
2. to really make sure you haven't moved anything, temporarily use the Time Remapping feature (right click on your layer and Time->Enable Time Remapping) and see if you CTI shows the exact frame on your CTI Display
if it's not - the layer has been shifted so nudge until it's in place - Alt/Option+PgUp/PgDn
Ahaha! Thanks, the framerate was indeed off by a fraction. Elusive details always get me.