The netlist wouldn't get updated if you edit one of the included files - there's no need, since it hasn't changed.
However, I suspect that what you're saying is that if you have set up a file to be included via Model Libraries or Definition file, and then edit that file between runs, you don't see the impact of any change? If so, that's a consequence of spectre running in "interactive" mode. In "interactive" mode, spectre does not exit after each simulation, so that a parameter change can be efficiently re-run by just changing the value in spectre's memory rather than having to start from scratch.
So if you are editing the file, you either can use the Edit button on the Setup->Model Libraries form (this will tell ADE that the file has changed, and hence spectre must be restarted), or you can just hit the Simulation->Stop menu before running again, or you could use:
envSetVal("spectre.envOpts" "controlMode" 'string "batch")
before starting ADE (but this will reduce performance a bit if you are doing parametric sweeps and so on - but these days it should not be that significant).