Spent hours comping a vocal from 40 lanes of audio. Open it today and it plays back late. Out of time. But the waveform is in the right place! I’ve tried everything. There are no FX or inserts. No timing applied. No bus re-routing. It is visually in the right place, but plays late. Anything you can think of - it took hours and the only other version is pre-comp 
If you have one part which is def in time, then loop over the top of a steady 4/4 beat audio file to ensure the vox track really is lined up. Zoom right and and drag the file with quantize off until it sounds right.
There is also the option to adjust/offset an audio tracks timing.
Hope I’ve understood your issue
I think the user above may have it. check the inspector and see if a timing offset has been applied. easy to do by mistake. I did it once and a track played back 2 seconds late. took me a few minutes before I remembered this parameter and reset it. another possibility; maybe you changed the tempo of the song by accident? check that it is the same as an earlier version of the song if you have one. ed