I can't see LE making up a cadaver dog hit. I hope not. It would be not only unethical but also very stupid IMO. It could bite them in the bottom. If they later solve the case and want to prosecute someone but the working theory what happened to Lisa doesn't include her lying dead in the bedroom at all they would be giving an out to the defendant. Their attorney would be all over this hit. "Yeah, so you say that my client killed Lisa in [insert place] but that can't be true, the cadaver dogs hit in her parents' bedroom. If the dogs hit you must acquit."
I completely agree. I don't think they made up the hit at all, I think it was real. And it was the basis for them getting a search warrant to return with a team of white suits and another dog.
And during that search, they did not remove carpet from the area of the previous dog's "hit".
I think it's pretty clear that although the first dog hit there, the one they brought out to confirm did not. And so they dropped the investigation of that area of the carpet and left it intact.