@Fizz, yes he did. But he is not an official spokesperson, he is just a private citizen. citizens make mistakes due to a lack of knowledge. We now have more than just the raw footage of the misfire, we have recording of Hamas operative discussing this and admitting (among themselves) that it was a PIJ rocket, just as we have with Malaysia air and Russian operatives in Donbas.
I wasn't an interception, as it would be (to the best of my knowledge) that a rocket is intercepted over Gaza. Also, you can see other footage of interceptions, barrages are intercepted together, not just one rocket.