Wet handling, programme movement and the garment's construction can all affect shape. Stretching does not by itself prove that the washing machine used excessive heat.
Understanding this situation
Check the care label, chosen programme and drying instructions. Supporting a wet knit and using the specified drying position can be as important as the wash setting. Hanging a heavy wet item may introduce a separate change after it leaves the machine.
A useful next step
Retain the label and describe whether the shape changed during washing or subsequent handling. Do not repeat an unsuitable programme as a test. If several correctly treated items are damaged with other abnormal machine symptoms, include both patterns in the repair enquiry.
Manuals and supporting guidance
Model-specific instructions take priority. These references support the practical principles discussed here; they do not diagnose your appliance.