This just happened to me, i was editing my 14 minutes long replay, i had the timeline filled with keyframes (very elaborate shots and movements) and somewhere in the timeline i messed up a time keyframe making it 3 seconds longer than normal
Since i sync up the replay mod footage with my screen record like a mutlicamera setup, the difference in time was very noticeable
So to fix the issue, i had to go through every single time keyframe to check if the difference between Replay Time and Timeline Time was constant, this took me ages and could have been way easier if a Label in the GUI could tell me the difference in time between Replay and Timeline Time