If your hull # is 1212 and down, you should have a single rocker switch in your panel for generator operation. On boats equipped this way, the generator control module is the problem. Short of replacing the module, all you can try is to depower the generator control system by unplugging the module from the generator harness, let it rest 5 minutes and them plug it back in.
If your hull # is 1213 and up, you should have a round Kohler gage on your ignition panel. It has sealed switches with mylar covering the contacts. The "start" switch on the Kohler control could be sticking.
Intermittent electrical problems like this are very difficult for the dealer to diagnose so you may want to watch it and see if the problem re0occurs and if so, how frequently. However, if the generator starter motor fails to disengage when the generator starts itself, you should get it repaired immediately.