The dog wasn't tracking on the way up, she was very excitable and pulling hard - Luke was not looking for an"alert" - he took the dog originally for safety.
He did call looking for Jodi - he didn't call back again because he was afraid he might get Jodi into trouble if she was somewhere she wasn't supposed to be. He started to think later still that maybe Jodi had"dumped"him for some reason (14 year old, remember). Why didn't Judy call back to check on her daughter? Why, knoWing Jodi hadn't been where she was supposed to be nearly an hour after shewas supposed to arrive did Judy wait another 40 minutes after Jodi was supposed to arrive home before contacting Luke?
The evidence doesn't support Luke being told Jodi had left to meet him - only that she'd left, or was out. Judy herself said she assumed, because Luke had called, he and Jodi must have been planning to meet up at some point. The police would not accept any of Luke's thoughts on why Jodi hadn't turned up - with the info in 'this post you can see it's entirely possible Jodi could have returned home from wherever she was Whitten like called, and got into a fight with her mum.