Ofc. Mackenzie was conducting a drug investigation in 2011 (before Jardines was decided). He received information from a confidential informant that Ponce was selling meth from his residence. The CI also provided other information about other dealers which Mackenzie knew to be true. Mackenzie verified the information from the CI by conducting his own surveillance (during which he didn't actually see drugs, but he saw activity which he knew through training to be consistent with drug trafficking), and by comparing it to information received from another informant. Then he ran a drug dog on the exterior of Ponce's garage, and the dog alerted. He ran the same dog on 30 other houses in the neighborhood, and the dog did not alert.
Pretty thorough investigation (especially compared to the embarrassingly half-assed crap the cops in Jardines did). After all that, he applied for a search warrant. A subsequent search of Ponce's residence revealed exactly what he thought it would (meth and guns). Ponce moved to suppress the evidence, arguing that the information in the affidavit didn't amount to probable cause. His motion to suppress was denied, so he pled guilty and appealed.
Now that the supreme court has ruled that we can't run dogs on the outside of people's houses without a warrant, Ponce's appeal looks like it has a little bit more of a chance. And the prosecution (for some reason) conceded that without the dog sniff, the affidavit didn't establish PC. The Tenth Circuit decided not to decide whether or not the affidavit established PC, and instead turned to the good faith exception.
As has been discussed in other decisions, the good faith exception to the exclusionary rule means that even if a warrant turns out to have been issued without probable cause, the evidence is still admissible unless one of the following applies: 1- when the issuing magistrate was misled by an affidavit containing false information or information that the affiant would have known was false if not for his reckless disregard of the truth; 2- when the issuing magistrate wholly abandons her judicial role; 3- when the affidavit in support of the warrant is so lacking in indicia of probable cause as to render official belief in its existence entirely unreasonable; 4- when a warrant is so facially deficient that the executing officer could not reasonably believe it was valid; and 5-when the warrant's flaw results from recurring or systemic police negligence. If none of those exist, then the evidence won't be suppressed even if a warrant later turns out to be defective.
In this case, the Tenth didn't decide whether or not the warrant was defective. They just decided that even if the warrant was defective (which is to say, even if the dog sniff was necessary to establish PC), the police weren't in a position where they should have known that. The good faith exception applies, the evidence is admissible, and Ponce's conviction stands.