Where light as shadows ...

have the set of 3 ordered in any size and rattles part of machanismuses is for the movement of the "flame" in charge.

the strategic placement you have only four options

you send the set back and hopes that you get a new (which is equal to rattle all three probably no coincidence)
They are prepared outside and looking through the window - that is, the electronics do not last long because of the moisture
using ear plugs
or one fixes the bug. It's pretty easy, by man cotton sticks to the beating of the inner housing connector.

three stars because that is "flame image" 1a and a forgotten deglaze the "flame" is no danger.