A seek changes the playback position and can expose a source or player timing problem that is different from a constant output delay.
Why this happens
If dialogue is aligned at the start but becomes misaligned after jumping forward, keep that sequence in the report. A fixed delay that exists from the first second suggests a different comparison from one triggered by a seek. Players need to resume audio and video together at the new position, and a problematic source or playback path may not settle in the same way each time. Repeatedly adding a new global delay can conceal the trigger without explaining it.
Return to ordinary playback and compare a single short seek on the same item. Note whether a pause/resume or reopening the item restores alignment, then compare another on-demand source if available. Do not assume that a correction appropriate for a downloaded file has the same effect on every live or replay route. Use the player’s documented synchronization control only after establishing whether the mismatch remains constant. The useful evidence is the starting position, the seek action and what happened afterward, not simply a statement that all sound is late.
A useful way to work through it
Confirm whether playback starts in sync before making a seek.
Repeat one short jump and record when the mismatch appears.
Compare another item before saving a global audio-delay correction.