EP's are notorious for fluctuating tq's at low power settings in cooler weather/cool nights when they are rigged to generally fly in warm/hot weather , fly during the day (average 25-30 oC day) no problem , fly the same machine at night do a low power decent to an airport or low speed/power search for example and you will have massive tq fluctuations of up to 10 % , nothing to do with Auto Pilot , it just makes it worse, if you engines are rigged for the general climate they operate in , being Cyprus average day 25oC , machines run fat dumb and happy in the warm climate all the time but because the 3D has the bleed valve at P2.8 air unlike the old 3B at P2.5 air it has a greater impact to the P3 air to the engine controls, as less power is needed and the air is cooler the bleed valve flutters as it is right on the open/close threshold and causes spikes in the P3 air as the engines start hunting one chases the other, easiest just split the tq about 4% , one engine bleed valve is definitely closed and the other definitely open , when the pilot pulls power again to normal levels match the engines again,
I have worked on EMS/SAR EP's for years in hot climates and the big Tq fluctuations always happen when the weather gets cooler or at night , I just got my pilots to get used to splitting tq's as soon as big fluctuations start and problem goes away.