When prefabs (reusable 3D model templates) have high poly counts, they break because hardware or software struggles to handle the excess data, straining rendering or memory.
High poly counts mean more geometry for engines (like Unity/Unreal) or devices to process—this can cause glitches, missing parts, or crashes. Unoptimized details (e.g., unnecessary subdivisions) or disabled LOD (Level of Detail) settings make it worse.
To fix it, reduce polys with a decimation tool (such as Blender’s Decimate modifier) or add LODs (simpler versions for distant views)—these steps ease the load while keeping key detail.