Comment yes, very common for appeal to instruct on the law (Score 3, Informative) 104
The appeals courts generally rule on the LAW, not on the FACTS. So when they overturn a decision they frequently remand it with an instruction (not a request) to decide it in accordance with a specific understanding of the law.
Why send it back rather than just deciding the outcome of the case? Because the appellant ruling on the law may or may not change the outcome of a case. Imagine someone confessed to a murder, and there were also witnesses. The appellant court might rule that as a matter of law the confession is not admissible. They'd remand the case to be tried without the confession. The murderer might well still be convicted based on witness testimony and other evidence. The appeals court doesn't hear from witnesses, they just rule on points of law. The trial court would need to judge guilt or innocence, while following the appellant court's instruction to not play the confession for the jury.