Stop working beneath an unsupported lid and arrange assessment of the hinge or support arrangement. Do not prop it with an unstable household object.
What the observation tells you
A falling lid can injure someone reaching into the cabinet. The fault may involve hardware or damage, and removing a hinge cover can expose spring-loaded parts. An improvised support can slip while the contents shift.
A useful next step
Keep children away and explain the lid behaviour when booking. Arrange safe food access or transfer without placing yourself underneath it. Leave hinge adjustment or replacement to the appropriate competent procedure.
Manuals and supporting guidance
Model-specific instructions take priority. These references support the practical principles discussed here; they do not diagnose your appliance.