Camera failing to detect motion

I purchased the ring cam plus” battery operated” to detect any motion in back yard! I’ve noticed if the motion setting is set on periodically or regular setting it will not pick up any motion no matter when there is motion! If I change setting to frequently, motion is caught every time! It seems when it’s in sleep mode, it won’t wake up with motion! I sent the camera back and purchased another one just like it! Same thing is happening! Is this normal? I would think if it’s in sleep mode, motion would wake it up without having to be set on frequently, which is going to drain battery! Please help!