All fg fpvs have this system built in to the pcm to avoid heatsoak damage to various components, pcm determines if/when/how long to turn on the fans after shut down, I wouldnt worry about it as it takes so many factors into consideration (ambient air temp , cyl head temp, drive cycle time just to name a few), try disconnecting the battery for 10 min to reset keep alive memory if your worried but I wouldnt be....