Occasional clicks or cracks can occur as temperatures change or automatic functions operate. The sound needs to be considered with its pattern and any visible damage.
What the observation tells you
A single brief sound is different from repeated heavy knocking, a broken shelf or ice striking a moving part. Do not flex the liner or fittings to recreate it. That adds force without showing what happened during normal operation.
A useful next step
Keep a short record of when it occurs, such as after loading or during a quiet period. If it is new, persistent or associated with warming, seek advice rather than declaring every crack normal.
Manuals and supporting guidance
Model-specific instructions take priority. These references support the practical principles discussed here; they do not diagnose your appliance.