While you can get thermal lags like this, it seems unlikely in this case. If the hypothetical hidden passages were only a few centimeters from the surface they would definitely show such a signal under appropriate conditions. But a rock wall that thin would have been obvious to any number of other observation techniques that have been used in the past. If the passages are further from the surface the thermal signal will start to disappear for a couple of reasons. First the thermal time constant gets long relative to a day. Secondly, the passages need to be human scale, or else cave-ins or detections be other means would have occurred. But if human scale, lateral heat spreading tends to blur any signal.
That leaves you with theories only the ancient astronaut or crystal energy crowds could believe. Theories like "The materials of these rocks were engineered to have different thermal characteristics so that they could be detected once a sufficiently advanced civilization developed." And they predicted how far in the future that would occur so that the engineered rocks would be on the surface after the theft of the surfacing stones and erosion/weathering of the layers underneath.
As an aside, I thought the pyramids were mostly constructed of limestone with granite only on a few interior walls and features. Same arguments about emissivity apply to limestone. If granite is seen on currently exposed faces of the pyramids that is a far bigger clue to interior passages than any thermal differences.