"Audio Tick" is an audible artifact in the audio track. These are caused by edits that cut in between samples or peaks of an audio file and cause the output speakers to change voltage rapidly.
Audio tick impacts the Technical quality of the asset. The waveform is causing a jump in voltage, resulting in an artifact that may manifest as an annoyance to the viewer. Not likely creative intent given the context of a scene.
Audio Tick may be a mouth noise from the actor or VO actor. Could also have been mis-flagged and is really a footstep, hand tap, or paper movement.
Audio tick occurs during silence or is very loud over dialogue. Does not appear to be the creative intent.
How to Prevent:
Full review of all audio elements as they interact with each other in the final mix, and manually cleaning up offending elements.
Affected dialogue should be replaced with ADR or a different take. If in silence, it must be masked by room tone or environmental effects.
Isolating offending element and performing a de-crackle or de-pop to remove the introduced element without significantly affecting the final mix.