There appears to be a memory leak in FCanvasBatchedElementRenderItem::Render_GameThread, depending on the path taken. If the first branch (if( Data->BatchedElements.HasPrimsToDraw() )) is taken, Data is deleted by the render thread, but nothing appears to be deleting Data if we don’t take the first branch. If FCanvas::Allow_DeleteOnRender is set on FCanvas::AllowedModes, Data will be cleared without deleting that memory.
Also note that FCanvasBatchedElementRenderItem::Render_RenderThread DOES delete Data in that case - but Render_GameThread doesn’t.