Ask what was checked, under which conditions and what remains uncertain. An intermittent problem not appearing during a visit is different from a confirmed explanation of why it happened.
What the observation tells you
Share existing photographs, recordings and the sequence of events without demanding repeated unsafe tests. A previous electrical trip, leak near electrics or unexpected start should remain part of the assessment even if the appliance currently appears normal. Ask whether further use is considered appropriate.
A useful next step
Keep the written findings and agreed next step. If the symptom returns during permitted normal use, stop as advised and report the new event with its context.
Manuals and supporting guidance
Model-specific instructions take priority. These references support the practical principles discussed here; they do not diagnose your appliance.