I have several questions.
Does Poppy have any retained puppy teeth? If so they need to come out and this might be the cause of the odor you are smelling. Could she have a yeast infection in the hair around her mouth? Are you feeding fish oil in her food? What do you mean she is "deflead" and "dewormed" regularly? Are you using some sort of flea dip or topical application? If she is on a Heartworm preventative that is broad spectrum this would take care of most parasites and the need for deworming would not be necessary. As for bathing monthly as a contrast I personally bath mine weekly and comb/brush daily. If I waited a month between bathes with Pebbles she would smell like a barn
There are spritzes that you can buy to help between bathes but I do think you need to bathe more often. Minimum more like 10 to 15 days. Good luck.