Small decorations can have heat and movement limits different from the main fabric. Loose or damaged attachments can also come off during tumbling.
Understanding this situation
A laundry bag does not override the garment's drying instructions or make sharp detachable parts safe. The complete construction, including glue and backing, needs to be suitable.
A useful next step
Follow the garment maker's care method and keep uncertain items out of the dryer. If pieces are missing afterwards and a new noise appears, stop further use and report the contents. Do not probe internal gaps to find loose decorations.
Manuals and supporting guidance
Model-specific instructions take priority. These references support the practical principles discussed here; they do not diagnose your appliance.