As mentioned, this breed is famous for a transition that it makes, referred to as the puppy uglies. The soft puppy coats falls out, there is a stage where the pup looks just terrible with thinning fur and sometimes even bald patches, and then everything rights itself when the adult coat comes in.
And with that, there is often a color change.
With red Pomeranians, this may indeed happen. An orange may darken to red or a red may lighten.
But, you do not necessarily lose the red.