you have to change the "Hold minimum power" slider for when the control variable is not available.
If the temperature that controls your fans is a virtual sensor, or a temperature sensor that is not directly wired to the Octo (like CPU, GPU temp for example), it won't be available to it until the service runs.
If that's the case, the Octo will default to its fallback value.
Okay thanks, I'll have a look at that. Its just that I have 17 fans hooked up and one of them makes a clunking noise when cold so its quite the racket. Thanks.