Where a cooker has a manufacturer-designed divider, it forms part of a particular operating arrangement. It is not an ordinary tray or an optional barrier for every mode.
What the observation means
Correct location, compatible accessories and mode selection can all matter. A homemade divider or a part from another model does not reproduce the intended design.
A useful next step
Follow the exact owner's procedure while the cavity is cool. If the divider is damaged or will not locate securely, leave the special mode unused and seek advice. Do not improvise with foil, sheet metal or a baking stone to divide the cavity.
Manuals and supporting guidance
Model-specific instructions take priority. These references support the practical principles discussed here; they do not diagnose your appliance.