These cases reflect the near-universal rule that state court judges in Utah love Utah's courts (and laws), whereas California state court judges often love California's courts (and laws). Hence the competing lawsuits -- and multifaceted litigation -- here.
The Court of Appeal ultimately holds that the later-filed California lawsuits can go forward. Which is fine, and accurately reflects the controlling legal principles.
But, as a practical matter, that Utah case is going to be resolved first. At which point claim preclusion (and the Full Faith and Credit Clause) will likely apply.
But, yes, Justice Snauffer is correct: it's not over yet. So the FFC Clause doesn't apply.
Yet.