Some methods use a perforated container to expose food to steam and a lower tray to catch drips. The exact arrangement depends on the oven and recipe.
What the observation means
Replacing that combination with a closed deep dish can change steam access and liquid collection. An unsupported tray can also spill when pulled forward. Use only accessories approved for the appliance and the required shelf positions.
A useful next step
Check the loading diagram rather than copying the arrangement from another steam oven. Record the accessory type if results are unexpectedly wet or uneven. Do not place a collecting dish on the cavity floor unless the model's instructions expressly permit that position.
Manuals and supporting guidance
Model-specific instructions take priority. These references support the practical principles discussed here; they do not diagnose your appliance.