My husband says:
Charliehall: “Not clear what the problem with the Yerushalmi is, or why we would not follow it, especially when the psak of the Bavli is unclear. But we clearly do not do regularly follow the Yerushalmi.”
In the Megilas Ester (the perush on the Rambam, not the sefer in Tanakh) on the shorashim preceding the Sefer HaMitzvos (shoresh #6), he says that the Rambam will posken like the Yerushalmi or Midrashei Halacha (Sifra and Sifre) when the halacha is not clearly resolvable based on the Bavli.
Here’s an example of poskening like the Sifra. The Sifra interprets the pasuk from which we derive the halachos of ona’ah (“ki tikneh me’amisecha… -Vayikra 25:14) to also mean that we should prefer buying from Jews over goyim, even at a (slight?) financial loss. The Chofetz Chayim brings this down l’halacha with respect to etrog suppliers. Etrog suppliers are supposed to buy from Jewish wholesalers rather than goyishe wholesalers, and that is because of this Sifra. (Sha’arei Tziyun OC 648:76).